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Python import dependencies
Question: I am dynamically creating some python code that I want to run inside a
wrapper. Here is an overly simplified example.
[wrapper.py]
import cv2
img = cv2.imread('pic.png',0)
__import__("fragment")
cv2.imshow('pic',img)
[fragment.py]
img = cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)
I want the wrapper to set up any imports and variables, then import the
fragment which will do stuff (i.e. make the image grayscale) and then do some
standardized stuff afterwards (i.e. display image).
The fragments will be changing (genetic algorithm) so I would prefer to keep
them separate from the setup which will be constant and will just get make
manipulating the fragments more complicated.
When I run the program I get dependency errors on the fragment because cv2 and
img are not defined (scope errors). Is there a way to achieve this either with
a correction to the method I have used above or with another method?
I expect I might be able to also create the composite of the files in ram and
then exec it or write over the fragment with a version of itself that contains
all of the needed wrapping, but I wanted to see if there was something cleaner
first.
Sincerely, Paul.
Answer: > The fragments will be changing (genetic algorithm) so I would prefer to keep
> them separate from the setup which will be constant and will just get make
> manipulating the fragments more complicated.
Whatever the complexity of the genetic algorithms you implemented in
`fragment.py` is, I do not see how importing `cv2` (and eventually more
modules) will impact it in a way or an other.
However, I agree with the first part of your statement in that you want to
respect the principle of _[separation of
concerns](https://en.wikipedia.org/wiki/Separation_of_concerns)_ and make your
code cleaner.
The solution I see for your problem is to set a configuration file `config.py`
in which you set all your imports. But importing `config.py` into other files
is useless unless you succeed to make modules such as `cv2` available
elsewhere once for all. You can achieve that by _[dynamically importing
them](http://www.diveintopython.net/functional_programming/dynamic_import.html)_
within `config.py` file:
cv2=__import__('cv2')
in your main program, `fragment.py` file or whatever module, you can make use
of `cv2` by simply running this:
import config
config.cv2.imread('pic.png')
`import config` β you do not need anymore to run: `import cv2`. This is
because this trick renders `cv2` as a global variable available across
multiple modules.
The same idea is valid for your other variables such as `img` that you need to
declare in your `config.py` file too.
Given these facts, here is my solution for your problem. Note that I am not
using classes and functions: I prefer to address your problem
straightforwardly and keep things too simple and clear instead.
**Organization of the code:**
The `config.py` file corresponds to your `wrapper.py`:
solution/
βββ application.py
βββ cfg
βΒ Β βββ config.py
βΒ Β βββ __init__.pyc
βββ gallery
βΒ Β βββ pic.png
βββ genalgos
βββ fragment.py
βββ __init__.py
**config.py:**
# This will make cv2 global and thus you won't need to import it in ./genalgos/fragment.py
# You can use the same idea for all your other imports
cv2=__import__('cv2')
imgc=cv2.imread('./gallery/pic.png') # imgc is global
**fragment.py:**
# The only import you can not avoid is this one
import cfg.config
# imgs is global
# By importing cfg.config you do not need to import cv2 here
imgf=cfg.config.cv2.cvtColor(cfg.config.imgc,cfg.config.cv2.COLOR_BGR2GRAY)
**application.py:**
import cfg.config
import genalgos.fragment
if __name__=="__main__":
"""
Display the image 'imgc' as it is in 'cfg/config' file
"""
cfg.config.cv2.imshow('Pic in BGR',cfg.config.imgc)
cfg.config.cv2.waitKey(0)
cfg.config.cv2.destroyAllWindows()
"""
Display the grascaled image 'imgf' as it is in 'genalgos/fragment' file which
itself is obtained after transforming imgc of 'cfg/config' file.
"""
cfg.config.cv2.imshow('PIC Grayscaled',genalgos.fragment.imgf)
cfg.config.cv2.waitKey(0) # Press any key to exit
cfg.config.cv2.destroyAllWindows() # Unpaint windows and leave
|
GAE Python get default bucket fxn returns None
Question: I'm a GCS newbie trying to write an app that uploads a file to a bucket I have
created. I've followed the tutorial and created a bucket using the browser
interface. However when I programmatically try to access my bucket, I get an
error. Instead of printing my default bucket name, my app ouputs "None". My
ENTIRE app code is as shown:
import webapp2
from google.appengine.api import app_identity
class MainHandler(webapp2.RequestHandler):
def get(self):
self.response.write(app_identity.get_default_gcs_bucket_name())
app = webapp2.WSGIApplication([
('/', MainHandler)
], debug=True)
What am I doing wrong?
Answer: **Update** :
Seems you can now create a default bucket **in the new console** too by
visiting your app engine's application settings in the cloud console
<https://console.cloud.google.com/appengine/settings?project=>
[](http://i.stack.imgur.com/ltbDK.png)
* * *
**Original** :
You're getting `NONE` because by default there's no longer a default bucket
> About default Cloud Storage buckets
>
> Applications created using the old App Engine console could use a default
> Cloud Storage bucket, which had free quota and didn't require billing to be
> enabled for the app. These applications continue to work as before in the
> Google Cloud Platform Console.
>
> However, new App Engine projects created in the Google Cloud Platform
> Console don't have a default Cloud Storage bucket. Instead you must use a
> standard Cloud Storage bucket as described above.
But since you manually created the bucket, you will already have its name and
so can probably skip `app_identity.get_default_gcs_bucket_name()` and hardcode
the bucket name or call it from a config variable, etc, etc.
You can then use the [gcloud-
python](https://github.com/GoogleCloudPlatform/gcloud-python) lib to upload
files to your bucket:
from gcloud import storage
client = storage.Client()
bucket = client.get_bucket('<bucket-name>')
my_file = bucket.blob('/path/to/be/saved/in/bucket')
my_file.upload_from_filename(filename='/path/to/local/file')
You'll have to
[vendor](https://cloud.google.com/appengine/docs/python/tools/libraries27#vendoring)
the gcloud lib if you're doing this on app engine.
All that said and done if you still want the old behaviour of getting the
default bucket which is in the format `<project-id.appspot.com>`, you can
follow [GAEfan's answer](http://stackoverflow.com/a/24237328/2295256), in
short:
> Go to the old console, appengine.google.com > Application Settings > Cloud
> Integration > Create
|
Run a executable by python at background and still running
Question: High! I have a executable made by py2exe whitch test if my vpn is connect or
not at infinit loop runinngi on Windows. I want to make run in background or
hiden, i searched for several forums and i found 2 scripts worked partialy.
1. rename script to "scrypt.pyw" and run py2exe again, the .exe hide when i run it, but close or vanish. Doesnt continues running after the click.
2. I am made another exe to call the fist one:
import os
import subprocess
os.chdir("C:\Users\dl\Documents\Log\Py")
proc = subprocess.Popen('ipLog.exe', creationflags=subprocess.SW_HIDE,
shell=True)
proc.wait()
or
os.chdir("C:\Users\dl\Documents\Log\Py")
proc = subprocess.Popen('ipLog.exe', creationflags=subprocess.SW_HIDE,
shell=True)
-Works but the first command still visible, and when i close it, the first exe call by it quit too.
3. I tried install a module call self.hide but i cant.
I am newbie in python and try to change my hobbies vb, vba to python.
Thanks for any help.
Answer: I found a solution in this thread [How to start daemon process from python on
windows?](http://stackoverflow.com/questions/12843903/how-to-start-daemon-
process-from-python-on-windows). Thank you all people helped with this thread,
help my script too.
|
Need to check if an answer in a quiz is correct (Python)
Question: So I have a dictionary with legislators and the parties they belong to. Five
questions are outputted with random names and parties and the input is either
Y or N. I need to now figure out how to check if its true or not but I am
stumped. The code:
from random import *
legislators = { "Tsang Yok-sing" : "DAB", "Albert Ho" :
"Democratic", "Lee Cheuk-yan" : "Labour", "James To" :
"Democratic", "Chan Kam-lam" : "DAB", "Lau Wong-fat" :
"Economic Synergy", "Emily Lau" : "Democratic" }
names = list(legislators.keys())
parties = list(legislators.values())
numberCorrect = 0
for i in range(0, 5):
name = names[randrange(len(names))]
party = parties[randrange(len(parties))]
ans = input("Does "+name+" belong to "+party+" (Y/N)?\n")
Just need to get any advice on where to start on this. Thanks a lot!
Answer:
from random import *
legislators = { "Tsang Yok-sing" : "DAB", "Albert Ho" :
"Democratic", "Lee Cheuk-yan" : "Labour", "James To" :
"Democratic", "Chan Kam-lam" : "DAB", "Lau Wong-fat" :
"Economic Synergy", "Emily Lau" : "Democratic" }
names = list(legislators.keys())
parties = list(legislators.values())
numberCorrect = 0
for i in range(0, 5):
name = names[randrange(len(names))]
party = parties[randrange(len(parties))]
ans = raw_input("Does "+name+" belong to "+party+ " Y/N?")
if ans == 'Y':
if legislators[name] == party:
print 'correct'
else:
print 'error'
elif ans == 'N':
if legislators[name] == party:
print 'error'
else:
print 'correct'
|
Wing IDE not stopping at break point for Google App Engine
Question: I'm new to Python, Wing IDE and Google cloud apps but have done a lot of
programming so hopefully the below question is not too stupid.
I've been trying for a couple of days to get Wing IDE to stop at a break point
on the local (Windows 7) Google App Engine. I'm using the canned guestbook
demo app and it launches fine and responds as expected in the web browser.
However breakpoints are not working. I'm not sure if this is important but I
see the following status message when first starting the debugger: Debugger:
Debug process running; pid=xxxx; Not listening (too many connections) ...
My run arguments are as per the recommendation in the Wing IDE help file
section "Using Wing IDE with Google App Engine", namely: C:\x\guestbook
--max_module_instances=1 --threadsafe_override=false
One problem I found when trying to follow these instructions. The instructions
say go into Project Properties and the Debug/Execute tab and set the Debug
Child Processes to Always Debug Child Process. I found this option doesn't
exist.
Note also that in the guestbook app, if I press the pause button, the code
breaks, usually in the python threading.py file in the wait method (which
makes sense).
Further note also that if I create a generic console app in Wing IDE,
breakpoints work fine.
I'm running 5.1.9-1 of Wing IDE Personal. I've included the Google appengine
directory and the guestbook directories in the python path.
Perhaps unrelated but I also find that sys.stdout.write strings are not
appearing in the Debug I/O window.
Thanks in advance for any assistance.
Regards Adam
Answer: As often happens with these things, writing this question gave me a couple of
ideas to try. I was using the Personal edition ... so I downloaded the
professional edition ... and it all worked fine.
Looks like I'm paying $95 instead of $45 when the 30 day trial runs out.
|
Return all tags and values of a given object within xml document in Python
Question: I have xml which looks like this...
<CONFIG2>
<OBJECT id="{2D3474AA-9A0F-4696-979C-1BCE9350F3BD}" type="3" name="Test2" rev="1">
<RULEITEM>
<ID>{BF7D00C5-57BC-4187-9B07-064BA5744A12}</ID>
<PROPERTIES>
<columnname/>
<columnvalue/>
<days>|</days>
<enabled>1</enabled>
<eventdate>0001-01-01</eventdate>
<eventtime>00:00:00</eventtime>
<function>average</function>
<parameters/>
<stattype>standard</stattype>
</PROPERTIES>
<ITEM>
<ID>{61C82F62-8F31-4754-A705-7CCBB34C6FD4}</ID>
<PROPERTIES>
<actionindex>0</actionindex>
<actiontype>eventlog</actiontype>
<severity>error</severity>
</PROPERTIES>
</ITEM>
</RULEITEM>
<PROPERTIES>
<groups>|</groups>
</PROPERTIES>
</OBJECT>
I am trying to return everything within OBJECT and /OBJECT.
For example, I would like to return all tags and values for the OBJECT where
type="3" and name="test2".
Here is my current python script...
import xml.etree.ElementTree as ET
tree = ET.parse(r'C:\Users\User\Desktop\xml\config.xml')
root = tree.getroot()
objectType = input("What object type are you looking for?: ")
for item in root.findall('OBJECT'):
if item.attrib['type'] == objectType:
print(item.get('name'))
objectName = input("What is the name of the object you are looking for?: ")
for item in root.findall('OBJECT'):
if item.attrib['type'] == objectType and item.get('name') == objectName:
print(list(item))
This returns...
<Element "RULEITEM' at 0x00064F3C0>, <Element 'PROPERTIES' at 0x0064FB40>
I like it to return the entire object and all tags and values. Does anyone
know how I could do this?
Thanks!
Answer: Consider adjusting second loop by using another `findall()` iteration on all
of `OBJECT's` children and grandchildren and so forth using (`//*`). Also,
consider appending to a pre-defined list instead of `list()` (which would have
broken each character of the loops' text item) and condition it to remove
`None` values (i.e., empty nodes). Finally, use the `tag` and `text` property
of the node:
... same code as above...
values = []
for item in root.findall('OBJECT'):
if item.attrib['type'] == objectType and item.get('name') == objectName:
for data in root.findall("OBJECT//*"):
if data.text is not None:
values.append(data.tag + ': ' + data.text)
for v in values:
print(v)
#What object type are you looking for?: 3
#Test2
#What is the name of the object you are looking for?: Test2
#RULEITEM:
#
#ID: {BF7D00C5-57BC-4187-9B07-064BA5744A12}
#PROPERTIES:
#
#days: |
#enabled: 1
#eventdate: 0001-01-01
#eventtime: 00:00:00
#function: average
#stattype: standard
#ITEM:
#
#ID: {61C82F62-8F31-4754-A705-7CCBB34C6FD4}
#PROPERTIES:
#
#actionindex: 0
#actiontype: eventlog
#severity: error
#PROPERTIES:
#
#groups: |
|
How to sort a list with duplicate items by the biggest number of duplicate occurrences - Python
Question: I have a
list1 = ["one", "two", "two", "three", "four" , "five", "five", "five", "six"]
and the Output should be
list2 = ["five" , "two", "one", "three" , "six"]
* `"five"` is the first element because in list1 has the highest number of occurrences (3)
* `"two`" is the second element because in list1 has the next highest number of occurrences (2)
* `"one"`, `"three`" and `"six"` have the same lower number of occurrences (1) so they are the last in my `list2` \- It doesn't really matter what position they will be as long as they are after "five" and "two". On short, `list2 = ["five" , "two", "six", "three" , "one"]` or `list2 = ["five" , "two", "three", "one" , "six"]` or any other variations are accepted.
I could solve this by creating a dictionary to store the number of occurances
and then create a new list with my items ordered by the dict
my_dict = {i:list1.count(i) for i in list1}
but I need something cleaner
Answer: You could use a list comprehension and
[`Counter`](https://docs.python.org/3/library/collections.html#counter-
objects):
from collections import Counter
print([element for element,count in Counter(list1).most_common()])
Outputs:
['five', 'two', 'three', 'six', 'four', 'one']
|
wx.TextCtrl is blank for very long strings
Question: I'm trying to display the string representation of a list of many float items
in a wx.TextCtrl using the SetValue() method.
As soon as the length of the string to be displayed reaches 6151 characters
the TextCtrl goes blank and does not display the string. I can still copy
portions of the text control as normal and paste them somewhere (such as a
text editor) but the characters in the text control itself don't appear on the
screen.
Why isn't the text control's value displayed in the text control? How do I
make it display the string if it's longer than 6150 characters?
This happens when setting the text control's value using the SetValue method
and when typing in the text control.
Changing the max length for the text control didn't help.
Environment:
* Windows 10 (64 bit)
* Python 2.7.10
* wxPython 3.0
Example code:
import wx
import os
class MainWindow(wx.Frame):
def __init__(self, parent, title):
wx.Frame.__init__(self, parent, title=title, size=(200,-1))
self.control = wx.TextCtrl(self)
self.control.SetMaxLength(10000) #doesn't help
self.sizer = wx.BoxSizer(wx.VERTICAL)
self.sizer.Add(self.control, 1, wx.EXPAND)
self.SetSizer(self.sizer)
self.SetAutoLayout(1)
self.sizer.Fit(self)
self.Show(True)
app = wx.App(False)
frame = MainWindow(None, "Sample editor")
app.MainLoop()
Answer: It looks like a bug. According to the
[this](https://groups.google.com/forum/#!topic/wxpython-users/m_6SYxkiI00), it
should max out at 64K since Windows 98 unless the operating system you have
has some kind of odd limit. You can actually increase the number of characters
displayed by using one of the `wx.TE_RICH` style flags.
I was able to replicate your issue on Windows 7 with Python 2.7 and wxPython
3.0.2 using the following code:
import wx
########################################################################
class MyPanel(wx.Panel):
""""""
#----------------------------------------------------------------------
def __init__(self, parent):
"""Constructor"""
super(MyPanel, self).__init__(parent)
self.text = wx.TextCtrl(self, value="y"*7000)
btn = wx.Button(self, label='Line Length')
btn.Bind(wx.EVT_BUTTON, self.onLength)
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(self.text, 0, wx.EXPAND|wx.ALL, 5)
sizer.Add(btn, 0, wx.CENTER|wx.ALL, 5)
self.SetSizer(sizer)
#----------------------------------------------------------------------
def onLength(self, event):
""""""
print len(self.text.GetValue())
########################################################################
class MyFrame(wx.Frame):
""""""
#----------------------------------------------------------------------
def __init__(self):
"""Constructor"""
super(MyFrame, self).__init__(parent=None, title='Test')
panel = MyPanel(self)
self.Show()
if __name__ == '__main__':
app = wx.App(False)
frame = MyFrame()
app.MainLoop()
If I add the `wx.TE_RICH` flag and call `Layout()`, I can make it work though:
import wx
########################################################################
class MyPanel(wx.Panel):
""""""
#----------------------------------------------------------------------
def __init__(self, parent):
"""Constructor"""
super(MyPanel, self).__init__(parent)
self.text = wx.TextCtrl(self, value="y"*7000, style=wx.TE_RICH)
btn = wx.Button(self, label='Line Length')
btn.Bind(wx.EVT_BUTTON, self.onLength)
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(self.text, 0, wx.EXPAND|wx.ALL, 5)
sizer.Add(btn, 0, wx.CENTER|wx.ALL, 5)
self.SetSizer(sizer)
self.Layout()
#----------------------------------------------------------------------
def onLength(self, event):
""""""
print len(self.text.GetValue())
########################################################################
class MyFrame(wx.Frame):
""""""
#----------------------------------------------------------------------
def __init__(self):
"""Constructor"""
super(MyFrame, self).__init__(parent=None, title='Test')
panel = MyPanel(self)
self.Show()
if __name__ == '__main__':
app = wx.App(False)
frame = MyFrame()
app.MainLoop()
You should report this bug here: <http://trac.wxwidgets.org/>
|
What is the preferred way to import pylab at a function level in Python 2.7?
Question: I have written a relatively simple function in python that can be used to plot
the time domain history of a data set as well as the frequency domain response
of a data set after a fast fourier transform. In this function I use the
command `from pylab import *` to bring in all the necessary functionality.
However, despite successfully creating the plot, I get a warning stating
> import * only allowed at the module level.
So if using the command `from pylab import *` is not the preferred
methodology, how do I properly load all the necessary functionality from
pylab. The code is attached below. Also, is there a way to close the figure
after the function is exited, I have tried `plt.close()` which is not
recognized for subplots?
def Time_Domain_Plot(Directory,Title,X_Label,Y_Label,X_Data,Y_Data):
# Directory: The path length to the directory where the output file is
# to be stored
# Title: The name of the output plot, which should end with .eps or .png
# X_Label: The X axis label
# Y_Label: The Y axis label
# X_Data: X axis data points (usually time at which Yaxis data was acquired
# Y_Data: Y axis data points, usually amplitude
from pylab import *
from matplotlib import rcParams
rcParams.update({'figure.autolayout': True})
Output_Location = Directory.rstrip() + Title.rstrip()
fig,plt = plt.subplots()
matplotlib.rc('xtick',labelsize=18)
matplotlib.rc('ytick',labelsize=18)
plt.set_xlabel(X_Label,fontsize=18)
plt.set_ylabel(Y_Label,fontsize=18)
plt.plot(X_Data,Y_Data,color='red')
fig.savefig(Output_Location)
plt.clear()
Answer: From the [matplotlib
documentation](http://matplotlib.org/faq/usage_faq.html#matplotlib-pyplot-and-
pylab-how-are-they-related):
> `pylab` is a convenience module that bulk imports `matplotlib.pyplot` (for
> plotting) and `numpy` (for mathematics and working with arrays) in a single
> name space. Although many examples use `pylab`, it is no longer recommended.
I would recommend not importing `pylab` at all, and instead try using
import matplotlib
import matplotlib.pyplot as plt
And then prefixing all of your `pyplot` functions with `plt`.
I also noticed that you assign the second return value from `plt.subplots()`
to `plt`. You should rename that variable to something like `fft_plot` (for
fast fourier transform) to avoid naming conflicts with `pyplot`.
With regards to your other question (about `fig, save fig()`) you're going to
need to drop that first `fig` because it's not necessary, and you'll call
`savefig()` with `plt.savefig()` because it is a function in the `pyplot`
module. So that line will look like
plt.savefig(Output_Location)
Try something like this:
def Time_Domain_Plot(Directory,Title,X_Label,Y_Label,X_Data,Y_Data):
# Directory: The path length to the directory where the output file is
# to be stored
# Title: The name of the output plot, which should end with .eps or .png
# X_Label: The X axis label
# Y_Label: The Y axis label
# X_Data: X axis data points (usually time at which Yaxis data was acquired
# Y_Data: Y axis data points, usually amplitude
import matplotlib
from matplotlib import rcParams, pyplot as plt
rcParams.update({'figure.autolayout': True})
Output_Location = Directory.rstrip() + Title.rstrip()
fig,fft_plot = plt.subplots()
matplotlib.rc('xtick',labelsize=18)
matplotlib.rc('ytick',labelsize=18)
fft_plot.set_xlabel(X_Label,fontsize=18)
fft_plot.set_ylabel(Y_Label,fontsize=18)
plt.plot(X_Data,Y_Data,color='red')
plt.savefig(Output_Location)
plt.close()
|
How does the __future__ module work in Python 2.7?
Question: In Python 2.7 using the `__future__` module and the `print_function` you can
use the python 3.X print function. My question is, how did the developers of
Python know what was coming in the future releases of Python? Or was this
module added to Python 2.7 after it was released? Here is the code I am
talking about:
from __future__ import print_function
print("Hello world!")
Answer: The [`__future__`](https://docs.python.org/3.5/library/__future__.html) module
was introduced in Python 2.1 in order to have access to upcoming
features/functions which will lead to incompatibilities with the current
implementation and is extended with each version if needed.
So the module gives the possibility to use those incompatible functions of
future versions in earlier versions. So you can make use of the upcoming
advantages of those functions.
There are three main reasons for that module as stated in the docs:
> `__future__` is a real module, and serves three purposes:
>
> * To avoid confusing existing tools that analyze import statements and
> expect to find the modules theyβre importing.
> * To ensure that future statements run under releases prior to 2.1 at
> least yield runtime exceptions (the import of `__future__` will fail,
> because there was no module of that name prior to 2.1).
> * To document when incompatible changes were introduced, and when they
> will be β or were β made mandatory. This is a form of executable
> documentation, and can be inspected programmatically via importing
> `__future__` and examining its contents.
>
|
python-couchdb: How to check if database already exists
Question: I am writing a small Python program that loads some documents into couchdb. It
would be very convenient to check whether a database with a certain name
already exists, so I can either create a new one or open the existing one.
What I want to do is something like this:
import couchdb
def connect(url, dbName):
server = couchdb.Server(url)
if dbName exists: # how do I do this?
return server[dbName]
else:
return server.create(dbName)
I know a try-except block would do the trick, but isn't there a more elegant
way?
Answer: The easiest way I can think is:
import couchdb
server = couchdb.Server("http://localhost:5984")
"dataBaseName" in server
Return `True` if a database with the name exists, `False` otherwise
<https://github.com/djc/couchdb-python/blob/master/couchdb/client.py#L88-L99>
|
validate email address with Python
Question: I'm trying to validate emails using [validate_email 1.3 : Python Package
Index](https://pypi.python.org/pypi/validate_email), like this:
from validate_email import validate_email
is_valid = validate_email('[email protected]',check_mx=True)
How can I speed this up? My `for` loop isn't very effective with amount of
emails I need to verify...
Answer: Only use `check_mx=True` the first time you encounter a domain. After that,
just use a regex to validate the address.
|
Loop through and compare spreadsheet cells in Python
Question: Please excuse the crude code and I'm sure there are better ways to accomplish
this but I am new to programming. Basically I have an excel file with 2
sheets, sheet 1 is populated in column A, sheet 2 is populated in A, B, and C.
I want to run through all of the cells in sheet 1 column A searching for a
match in sheet 2 column A and copy the info from B and C to sheet 1 if found.
The code below kind of works, it copies some data and populates it but it
doesn't really match up correctly and it seems to skip a lot of cells if they
are the same value as the previous cell. Any help would be greatly
appreciated.
import openpyxl
wb = openpyxl.load_workbook('spreadsheet.xlsx')
sheet1 = wb.get_sheet_by_name('Sheet1')
sheet2 = wb.get_sheet_by_name('Sheet2')
for row in sheet1['A1':'A200']:
for cell in row:
obj1 = cell.value
for row2 in sheet2['A1':'A2000']:
for cell2 in row2:
obj2 = cell2.value
if obj1 == obj2:
row = str(cell2.row)
site = 'B' + row
tic = 'C' + row
sheet1[site] = sheet2[site].value
sheet1[tic] = sheet2[tic].value
wb.save('spreadsheet2.xlsx')
Answer: Your question is a little unclear but if I understand you correctly this
should help:
import openpyxl
wb = openpyxl.load_workbook('spreadsheet.xlsx')
sheet1 = wb.get_sheet_by_name('Sheet1')
sheet2 = wb.get_sheet_by_name('Sheet2')
for i in range(1, 201):
if sheet1.cell(row = i, column = 1).value == sheet2.cell(row = i, column = 1).value:
sheet1.cell(row = i, column = 2).value = sheet2.cell(row = i, column = 2).value
sheet1.cell(row = i, column = 3).value = sheet2.cell(row = i, column = 3).value
wb.save('spreadsheet2.xlsx')
I was able to clean up the code by the using the `.cell()` method. If this
isn't what you need just comment and tell me what exactly you are trying to
do. Hope this helps!
|
How can I add an integer variable to an openmdao driver?
Question: I am confused by this openmdao error. Why is this being raised? Can I somehow
tell openmdao that I don't have gradients and to use finite differences? Why
is this raised for childWeight but not eta?
I can get past this problem by initializing al my variables as floating point
(eg. `root.add('childWeight', IndepVarComp('x',100))` ->
`root.add('childWeight', IndepVarComp('x',100.0))`), but I would like to
understand why this error was raised.
from openmdao.api import Component, Group, Problem, ScipyOptimizer, IndepVarComp
class gym(Component):
def __init__(self):
super(gym, self).__init__()
self.add_param('eta', 0.01)
self.add_param('childWeight', 240)
self.add_output('acc', 1)
def solve_nonlinear(self, params, unknowns, resids):
<...... parameters are used to produce objective "acc" ...>
unknowns["acc"] = ....
top = Problem()
root = top.root = Group()
root.add('gym', gym())
top.driver = ScipyOptimizer()
top.driver.options['optimizer'] = 'BFGS'
root.add('eta',IndepVarComp('x', 0.01))
root.add('childWeight', IndepVarComp('x',100))
root.connect('eta.x', 'gym.eta')
root.connect('childWeight.x', 'gym.childWeight')
top.driver.add_desvar('eta.x', 0, 1.0)
top.driver.add_desvar('childWeight.x', 0, 1000)
top.driver.add_objective('gym.acc')
top.setup()
top.run()
raises the error
File "script.py", line 98, in <module>
top.setup()
File "/usr/local/lib/python2.7/site-packages/openmdao/core/problem.py", line 694, in setup
self.driver._setup()
File "/usr/local/lib/python2.7/site-packages/openmdao/drivers/scipy_optimizer.py", line 91, in _setup
super(ScipyOptimizer, self)._setup()
File "/usr/local/lib/python2.7/site-packages/openmdao/core/driver.py", line 115, in _setup
(item_name, name, oname))
RuntimeError: Parameter 'childWeight.x' is a 'pass_by_obj' variable and can't be used with a gradient based driver of type 'BFGS'.
Answer: The problem is this line
root.add('childWeight', IndepVarComp('x',240))
You've created an integer variable. Try this instead:
root.add('childWeight', IndepVarComp('x',240.))
If you want to use finite-differences you will also want:
top.root.fd_options['force_fd'] = True
|
Solve for constants of 4-parameter (Rodbard Equation) using Python
Question: I am new to python and what I am trying to do is write an algorithm to solve
for the 4 unknown parameters in the Rodbard Equation where we are relating a
grayscale value measured using ImageJ to optical density calibration discs.
This equation is nonlinear and is written as y = c*((x-a)/(d-x))^(1/b) where
a, b, c, and d are unknown. I have the values of x and y for four point
(176.5, 0), (161.333, 0.1), (66.1667, 0.9), and (40.833, 2.5). Below, I have
posted my attempt to solve for these 4 unknowns. Any help to point me in the
right direction would be greatly appreciated!
import scipy.optimize as opt
def f(a, b, c, d):
0 == [c * ((176.5 - a)/(d - 176.5))**(1/b)]
0.1 == [c * ((161.333 - a)/(d - 161.333))**(1/b)]
0.9 == [c * ((66.1667 - a)/(d - 66.1667))**(1/b)]
2.5 == [c * ((40.833 - a)/(d - 40.833))**(1/b)]
return f
opt.curve_fit(a, b, c, d)
print a
print b
print c
print d
Answer: If you want to use curve_fit, you should do the following:
def f(x1, a1, b1, c1, d1):
return c1 * (((x1 - a1)/(d1 - x1))**1/b1)
x_data = np.array([176.5, 161.333, 66.1667, 40.833])
y_data = np.array([0., 0.1, 0.9, 2.5])
p0 = np.array([168., -0.01, -7.4, 35000.])
popt, pcov = opt.curve_fit(f, x_data, y_data, p0, None, False, True, ftol = 0.00001)
p0 is the initial guess and if you do not inform it, an array of all ones will
be assumed.
With the provided data I have tried with different params but I've not been
able to find a solution.
I hope this helps. Good luck!
|
Twillio Restclient in python
Question: I'm Using Twilio Rest API in python to send sms , Below is the code I'm using
to send SMS
SMS was being sent successfully by below code but I want body of text to be
declared as a variable. For example if I declare `ABC = "Test message"` then
body should be `Test message`.
from twilio.rest import TwilioRestClient
ACCOUNT_SID = "ACXXXXXXXXXXXXXXXXX"
AUTH_TOKEN = "YYYYYYYYYYYYYYYYYY"
client = TwilioRestClient(ACCOUNT_SID, AUTH_TOKEN)
message = client.messages.create(
body="Hello World!",
to="+12125551234",
from_="+15105551234",
)
print message.sid
If I use body = "ABC" it's sending message as "ABC" by sms i want declare
variable in this case ABC = "Test Message " i want Body as Testmessage
message = client.messages.create(
body="Hello Monkey!", # Message body, if any
to="+12125551234",
from_="+15105551234",
)
print message.sid
Is there any way to send declare variable as Message.
Answer: Hi if you write anything in a "" (string) then it will be treated as a String.
You should modify your code like below:
text = "Test Message"
message = client.messages.create(
body= text,
to="+12125551234",
from_="+15105551234",
)
print message.sid
Basically you should assign the variable `text` to `body` so now body is "Test
Message"
|
drone-kit Python is not connecting with Iris+
Question: I'm trying to build my first dronekit python program, and I'm doing some tests
with some examples but I couldn't connect to my UAV(Iris+). I plugged the usb
radio(3DR 915 MHz) and I put `vehicle = connect('/dev/ttyUSB0',
wait_ready=True)`. Actually I have no idea which string I should put in.
Thanks in advance guys, I need some help!
My code:
print "Start simulator (SITL)"
from dronekit_sitl import SITL
sitl = SITL()
sitl.download('copter', '3.3', verbose=True)
sitl_args = ['-I0', '--model', 'quad', '--home=-35.363261,149.165230,584,353']
sitl.launch(sitl_args, await_ready=True, restart=True)
# Import DroneKit-Python
from dronekit import connect, VehicleMode
import time
# Connect to the Vehicle.
print "Connecting to vehicle on: '/dev/ttyUSB0'"
vehicle = connect('/dev/ttyUSB0', wait_ready=True)
# Get some vehicle attributes (state)
print "Get some vehicle attribute values:"
print " GPS: %s" % vehicle.gps_0
print " Battery: %s" % vehicle.battery
print " Last Heartbeat: %s" % vehicle.last_heartbeat
print " Is Armable?: %s" % vehicle.is_armable
print " System status: %s" % vehicle.system_status.state
print " Mode: %s" % vehicle.mode.name # settable
# Close vehicle object before exiting script
vehicle.close()
# Shut down simulator
sitl.stop()
print("Completed")
Answer: Best place for getting dk support now is probably here:
<https://discuss.dronekit.io/c/python>
In answer, I have not tried this on Linux. I suspect the connection string is
correct, but you may have to also set the baud rate using baud=57600
|
Scraping using beautiful soup not working for a particular URL as expected
Question: I was trying to scrape some data off from a site using beautifulsoup on python
3.5(i'm working on eclipse) and requests from the site
'<http://www.transfermarkt.com/arsenal-
fc/startseite/verein/11/saison_id/2015>' which has some stats for footballers.
my code:
from bs4 import BeautifulSoup
import requests
r=requests.get('http://www.transfermarkt.com/arsenalfc/startseite/verein/11/saison_id/2015')
soup = BeautifulSoup(r.content, 'html.parser')
print (soup.prettify())
I expect a neat and pretty looking html code but all i get as output is this:
<html>
<head>
<title>
404 Not Found
</title>
</head>
<body bgcolor="white">
<center>
<h1>
404 Not Found
</h1>
</center>
<hr>
<center>
nginx
</center>
</hr>
</body>
</html>
For a different url it works. I have tried a couple of other url's and it
worked. But not for this one. Am I doing something wrong. Any suggestion is
appreciated. Thanks
Answer: You should use a user-agent to make the website think the request comes from a
browser. This worked for me:
from bs4 import BeautifulSoup
import requests
headers = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36'}
r=requests.get('http://www.transfermarkt.com/arsenalfc/startseite/verein/11/saison_id/2015', headers=headers)
soup = BeautifulSoup(r.content, 'html.parser')
print(soup.prettify())
|
Get NS and MX web information python
Question: Im trying to get information about two domain input with this code:
#! usr/bin/python
domainlist=[]
#Ask for domain 1
domain = raw_input("------------------------------------------\nIntroduce el primer domino de la pagina web:\n")
domainlist.append(domain)
#Ask for domain 2
domain = raw_input("------------------------------------------\nIntroduce el segundo domino de la pagina web:\n")
domainlist.append(domain)
print "-------------------"
#Declare Variable
#Find dns
def fundns():
import dns.resolver
idns = dns.resolver.query(i,'NS')
print "Los DNS de %s" % domain + " son:"
for server in idns:
print server
#Find mx
def funmx():
import dns.resolver
mx = dns.resolver.query(i,'MX')
print "Los MX de %s" % domain + " son:"
for rdata in mx:
print "Host", rdata.exchange
for i in domainlist:
fundns()
print "----------------------------------------"
funmx()
but I received this error:
> Traceback (most recent call last): File "ejercicio5.py", line 29, in funmx()
> File "ejercicio5.py", line 22, in funmx
I can see in the print all the information unless last `mx` registry, and I
don't know what is wrong...
Some one could help me?
Answer: You need to actually pass the domain names to your functions
import dns.resolver
domainlist = ['google.com', 'yahoo.com']
#Declare Variable
#Find dns
def fundns(domain):
idns = dns.resolver.query(domain,'NS')
print "Los DNS de %s" % domain + " son:"
for server in idns:
print server
#Find mx
def funmx(domain):
mx = dns.resolver.query(domain,'MX')
print "Los MX de %s" % domain + " son:"
for rdata in mx:
print "Host", rdata.exchange
for i in domainlist:
fundns(i)
print "----------------------------------------"
funmx(i)
Previously you were trying to use global variables, or so it seems.
The Output:
Los DNS de google.com son:
ns3.google.com.
ns2.google.com.
ns4.google.com.
ns1.google.com.
----------------------------------------
Los MX de google.com son:
Host alt3.aspmx.l.google.com.
Host alt2.aspmx.l.google.com.
Host alt4.aspmx.l.google.com.
Host alt1.aspmx.l.google.com.
Host aspmx.l.google.com.
Los DNS de yahoo.com son:
ns6.yahoo.com.
ns2.yahoo.com.
ns5.yahoo.com.
ns3.yahoo.com.
ns1.yahoo.com.
ns4.yahoo.com.
----------------------------------------
Los MX de yahoo.com son:
Host mta5.am0.yahoodns.net.
Host mta7.am0.yahoodns.net.
Host mta6.am0.yahoodns.net.
|
Python Attribute Error: type object has no attribute
Question: I am new to Python and programming in general (since December) and try to
teach myself some Object-Oriented Python and got this error on my lattest
project:
AttributeError: type object 'Goblin' has no attribute 'color'
I have a file to create "Monster" classes and a "Goblin" subclass that extends
from the Monster class. When I import both classes the console returns no
error
>>>from monster import Goblin
>>>
Even creating an instance works without problems:
>>>Azog = Goblin
>>>
But when I call an attribute of my Goblin class then the console returns the
error on top and I don't figure out why. Here is the complete code:
import random
COLORS = ['yellow','red','blue','green']
class Monster:
min_hit_points = 1
max_hit_points = 1
min_experience = 1
max_experience = 1
weapon = 'sword'
sound = 'roar'
def __init__(self, **kwargs):
self.hit_points = random.randint(self.min_hitpoints, self.max_hit_points)
self.experience = random.randint(self.min_experience, self.max_experience)
self.color = random.choice(COLORS)
for key,value in kwargs.items():
setattr(self, key, value)
def battlecry(self):
return self.sound.upper()
class Goblin(Monster):
max_hit_points = 3
max_experience = 2
sound = 'squiek'
Answer: You are not creating an instance, but instead referencing the class `Goblin`
itself as indicated by the error:
> AttributeError: **type** object 'Goblin' has no attribute 'color'
Change your line to `Azog = Goblin()`
|
Django command: How to insert newline in the help text?
Question: I was looking to do something like this, but for a Django management command:
[Python argparse: How to insert newline in the help
text?](http://stackoverflow.com/questions/3853722/python-argparse-how-to-
insert-newline-in-the-help-text)
Answer: You can do the following to set the formatter_class on the ArgumentParser
Django creates for you:
from argparse import RawTextHelpFormatter
from django.core.management.base import BaseCommand
class Command(BaseCommand):
def create_parser(self, *args, **kwargs):
parser = super(Command, self).create_parser(*args, **kwargs)
parser.formatter_class = RawTextHelpFormatter
return parser
|
How to execute external Python script with a program coded in Haxe?
Question: I have a Haxe program and I need to retrieve data from Wordnik API. Here are
the list of supported platform in Wordnik:
<http://developer.wordnik.com/#!/libraries>
I have no experience in all of these languages supported by Wordnik. However,
I think Python is the most feasible way to connect Wordnik API into my Haxe
program because Python is a scripting language and can be executed from
terminal command.
Perhaps, something like Haxe program execute the Python WITH some parameters.
Then the Python script retrieve data from Wordnik and then compile it into a
JSON or .txt file. Finally return back to Haxe program to parse the JSON or
.txt file. I am not sure how this thing can work, hence I am looking for
guidance here :).
Answer: One thing to look out for is using the [Python 3
version](https://github.com/wordnik/wordnik-python3) of the library, instead
of the [Python 2.7 one](https://github.com/wordnik/wordnik-python) which is
linked to on that overview page. Haxe's Python target [only supports version 3
or higher](https://github.com/HaxeFoundation/haxe/issues/4195).
There shouldn't be a need for a Python program serving as an interface between
Haxe and the Wordnik API - you could write
[externs](http://haxe.org/manual/lf-externs.html) describing the interface to
just use it directly from Haxe. An `extern` for a very simple class,
[`wordnik.models.Label`](https://github.com/wordnik/wordnik-
python3/blob/master/wordnik/models/Label.py), could look like this:
package wordnik.models;
@:pythonImport("wordnik.models.Label", "Label")
extern class Label
{
public var text:String;
public var type:String;
public function new()
{
}
}
With that, you can then use the API from Haxe:
package;
import python.Lib;
import wordnik.models.Label;
class Main
{
static function main()
{
var label = new Label();
label.text = "Test";
trace(label.text);
}
}
You can find a lot of examples of Python externs in [the Haxe standard
library](https://github.com/HaxeFoundation/haxe/tree/development/std/python/lib).
It also has wrappers for things that are a bit more complex to express, like
[`KwArgs`](https://github.com/HaxeFoundation/haxe/blob/development/std/python/KwArgs.hx).
|
Python - How to call the main fuction of a module in another module?
Question: I am trying to write a python module that calls the main function of another
module in its main function.
The module I am writing is called Trial.py and the module that contains the
function to be called is called `print_all.py` .
print_all.py is a module is a library called mrtparse. The library can be
found [here](https://github.com/YoshiyukiYamauchi/mrtparse).
Note that when I run `print_all.py` in the Linux shell it requires a file
(.gz) as argument as follows
$ python print_all.py updates.gz
`Trial.py` looks something like this:
from mrtparse import *
import gzip
import print_all
import os
from urllib2 import urlopen, URLError, HTTPError
def fn1():
Bla Bla
def fn2():
Bla Bla
def main():
mrtparse.print_all.main(updates.gz) //I want to do something like this
if __name__ == '__main__':
main()
All the modules and the files to be passed as arguments are in the same
directory. It seems like an easy to do thing but I am having such a hard time
with it.
Answer: you could in the script you want to run the main function from place main() in
the else statement instead of if **name** then import it in your script and
just run.
if __name__=='__main__':
pass
else:
main()
|
Python: import all submodules' method?
Question: I organized my helper method into this way:
[](http://i.stack.imgur.com/Tz9jc.png)
All the methods are used in the current file, so I need to import them like
this:
from helpers.utility_helper import *
from helpers.app_helper import *
from helpers.gmm_helper import *
from helpers.plot_helper import *
So I can directly use methods in each of the submodule. For example, use
`my_helper()` instead of `helpers.utility_helper.my_helper()`.
But this looks quite verbose, is it possible to combine them into one line?
Something may look like
`import * from helpers/*`
Answer: I would advise to use explicit imports instead of importing whole:
from helpers.utility_helper import my_helper, your_helper
This will help to avoid mistakes.
For short names you can use _as_ :
import helpers.utility_helper as util
import helpers.app_helper as app
import helpers.gmm_helper as gmm
import helpers.plot_helper as plot
It is quite normal practice.
|
HSV2BGR conversion fails in Python OpenCV script
Question: My script is supposed to take a greyscale image and map the values to hues.
#!/usr/bin/env python
import cv2
import numpy
infile = cv2.imread('Lenna.png')
infile = infile[:,:,0]
hues = (numpy.array(infile)/255.)*179
outimageHSV = numpy.array([[[b,255,255] for b in a] for a in hues]).astype(int)
outimageBGR = cv2.cvtColor(outimageHSV, cv2.COLOR_HSV2BGR)
cv2.imshow('dst_rt', outimageBGR)
cv2.waitKey(0)
cv2.destroyAllWindows()
It fails on the line with cvtColor and I get this error:
OpenCV Error: Assertion failed (depth == CV_8U || depth == CV_16U || depth == CV_32F) in cvtColor, file /tmp/opencv20150506-38415-u2kidu/opencv-2.4.11/modules/imgproc/src/color.cpp, line 3644
Traceback (most recent call last):
File "luma2hue.py", line 16, in <module>
outimageBGR = cv2.cvtColor(outimageHSV, cv2.COLOR_HSV2BGR)
cv2.error: /tmp/opencv20150506-38415-u2kidu/opencv-2.4.11/modules/imgproc/src/color.cpp:3644: error: (-215) depth == CV_8U || depth == CV_16U || depth == CV_32F in function cvtColor
Do I need to do something else to my outimageHSV array to make it ready for
cvtColor?
Answer: The error message implies that cv2.cvtColor expects an image with a (color)
depth of 8 or 16 bit unsigned int (8U, 16U) or 32 bit float (32F). Try
changing `astype(int)` to `astype(numpy.uint8)`
|
Python Deep Learning Keras: Wrong number of dimensions: expected 3, got 2 with shape
Question: I am new to Keras, a deep learning library and need your help. The model is
built without errors, but has the following issue when calling model.fit(X,
y):
TypeError: ('Bad input argument to theano function with name "~/machine_learning2/lib/python2.7/site-packages/keras/backend/theano_backend.py:380"
at index 0(0-based)', 'Wrong number of dimensions: expected 3, got 2 with shape (16, 40).')
This is similar as this one <https://github.com/fchollet/keras/issues/815> My
y train matrix is a matrix with multiple rows and one column.
One solution mentioned about converting y to 3d tensor with binary one-hot
coding. Is there an example of this?
Answer: You can use:
from keras.utils import np_utils
np_utils.to_categorical(y_train, n_classes)
for one hot encoding, where y_train is a train class vector and n_classes -
total number of a classes,
However, based on that the error description mentions (16, 40), rather than a
(Nx1), I suspect you might have an issue with your X as well.
|
Resolving ValidationError: [u"'' value has an invalid date format. It must be in YYYY-MM-DD format."] in Django 1.9.2?
Question: Earlier I created two fields & migrated everything. after that I tried to add
three fields `title`,`about`,`birthdate` into the model. I created a model
like this :
from __future__ import unicode_literals
from django.utils import timezone
from django.db import models
# Create your models here.
class APP1Model(models.Model):
name = models.CharField(max_length=120)
percentage = models.CharField(max_length=120)
title = models.CharField(max_length=100,default='Title')
birth_date = models.DateTimeField(blank=True, null=True)
about = models.TextField(max_length=100,null=True,default='About Yourself')
def __unicode__(self):
return self.name
But when I try to migrate in python shell, it is showing a validation error
like this:
Operations to perform:
Apply all migrations: admin, contenttypes, auth, app1, sessions
Running migrations:
Applying app1.0005_auto_20160217_1346...Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 345, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 348, in run_from_argv
self.execute(*args, **cmd_options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 399, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 200, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 92, in migrate
self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 121, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 198, in apply_migration
state = migration.apply(state, schema_editor)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 123, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards
field,
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/sqlite3/schema.py", line 221, in add_field
self._remake_table(model, create_fields=[field])
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/sqlite3/schema.py", line 103, in _remake_table
self.effective_default(field)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 210, in effective_default
default = field.get_db_prep_save(default, self.connection)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 728, in get_db_prep_save
prepared=False)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1301, in get_db_prep_value
value = self.get_prep_value(value)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1296, in get_prep_value
return self.to_python(value)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1273, in to_python
params={'value': value},
django.core.exceptions.ValidationError: [u"'' value has an invalid date format. It must be in YYYY-MM-DD format."]
How to rectify this? I tried all solution i read here but it doesn't work?
I am using Django: 1.9.2
My migration File
from __future__ import unicode_literals
from django.db import migrations, models
class Migration(migrations.Migration):
dependencies = [
('app1', '0004_auto_20160217_0427'),
]
operations = [
migrations.AddField(
model_name='app1model',
name='about',
field=models.TextField(default='About Yourself', max_length=100, null=True),
),
migrations.AddField(
model_name='app1model',
name='birth_date',
field=models.DateField(blank=True, default='', null=True),
),
migrations.AddField(
model_name='app1model',
name='title',
field=models.CharField(default='', max_length=100),
),
]
Answer: I went through the same problem some months back.I Just deleted the birthdate
field changes in all the migration Files inside migration folder. Then I
replaced the birthdate with this code:-
birthdate = models.DateTimeField(blank=True, null=True)
Then after applying migration ,it works fine...
|
Python - Limiting Number of Threads while Multithreading
Question: Code below.
import sys
import urllib2
import threading
import time
urls = ["http://www.google.com", "http://www.apple.com"]
def fetch_url(url):
html = urllib2.urlopen(url).read()
print html
f = open("Output.txt", "w")
e = open("ErrorUsers.txt", "w")
threads = [threading.Thread(target=fetch_url, args=(url,)) for url in urls]
for thread in threads:
try:
thread.daemon = True
thread.start()
except urllib2.HTTPError, e:
e.write(url + "\n")
except urllib2.URLError, e:
e.write(url + "\n")
for thread in threads:
thread.join()
Essentially I need to grab data from a large number of sites (we're talking in
the tens of thousands). I'm using the above code as a base, which works great,
however, the code freezes after the creation of 750 threads of so. I'm
wondering how to limit the number of active threads, or to like close a thread
once it finishes.
Answer: You can use a thread pool like the one implemented in multiprocessing.In the
following snippet, a maximum of 100 threads will be active any time.
from multiprocessing.pool import ThreadPool
urls = ["http://www.google.com", "http://www.apple.com"]
def fetch_url(url):
html = urllib2.urlopen(url).read()
print html
pool = ThreadPool(100)
pool.map(fetch_url, urls)
pool.close()
pool.join()
|
TestSuite vs "test discover"
Question: Is there any difference between creating a TestSuite and add to it all the
TestCases, or just running `python -m unittest discover` in the TestCases
directory?
For example, for a directory with two TestCases: `test_case_1.py` and
`test_case_2.py`:
import unittest
from test_case_1 import TestCaseClass as test1
from test_case_2 import TestCaseClass as test2
suite = unittest.TestSuite()
suite.addTest(unittest.makeSuite(test1))
suite.addTest(unittest.makeSuite(test2))
unittest.TextTestRunner().run(suite)
Or just `cd` into that directory and run `python -m unittest discover`.
I'm getting the same result with either way, but I'm interesting in knowing
whether one way is preferred over the other, and why.
Answer: I think an obvious benefit in favor of `discover` is maintenance.
* After a month, you get rid of `test_case_2` \- some of your code above will fail (the `import`) and you'll have to correct your above script. That's annoying, but not the end of the world.
* After two months, someone on your team made `test_case_3`, but was unaware that they need to add it to the script above. No tests fail, and everyone is happy - the problem is, nothing from `test_case_3` actually runs. However, you might counter that it's unreasonable to write new tests, and not notice that they're not running. This brings to the next scenario.
* Even worse - after three months, someone merges two versions of your above script, and `test_case_3` gets squeezed out again. This might go unnoticed. Until it's corrected, people can work all they want on the stuff that `test_case_3` is supposed to check, but it's just untested.
|
aws server : paramiko issue
Question: while i can normally connect to a server with ssh command :
>[ec2-user@dsi_valid_env:~/scripts]$ssh [email protected]
>[email protected]'s password:
but i am struggling to connect with paramiko for a python script :
>>> import paramiko
>>> ssh = paramiko.SSHClient()
>>> ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
>>> ssh.connect("172.XX.YY.ZZ",username="test",password="test")
paramiko.ssh_exception.SSHException: could not get keys from ssh-agent
do you have any idea of what i am doing wrong ?
below the debug stacktrace of my ssh.connect :
ssh.connect("172.XX.YY.ZZ",username="test",password="test")
DEBUG:paramiko.transport:starting thread (client mode): 0x24532d0L
INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_5.3)
DEBUG:paramiko.transport:kex algos:[u'diffie-hellman-group-exchange-sha256', u'diffie-hellman-group-exchange-sha1', u'diffie-hellman-group14-sha1', u'diffie-hellman-group1-sha1'] server key:[u'ssh-rsa', u'ssh-dss'] client encrypt:[u'aes128-ctr', u'aes192-ctr', u'aes256-ctr', u'arcfour256', u'arcfour128', u'aes128-cbc', u'3des-cbc', u'blowfish-cbc', u'cast128-cbc', u'aes192-cbc', u'aes256-cbc', u'arcfour', u'[email protected]'] server encrypt:[u'aes128-ctr', u'aes192-ctr', u'aes256-ctr', u'arcfour256', u'arcfour128', u'aes128-cbc', u'3des-cbc', u'blowfish-cbc', u'cast128-cbc', u'aes192-cbc', u'aes256-cbc', u'arcfour', u'[email protected]'] client mac:[u'hmac-md5', u'hmac-sha1', u'[email protected]', u'hmac-sha2-256', u'hmac-sha2-512', u'hmac-ripemd160', u'[email protected]', u'hmac-sha1-96', u'hmac-md5-96'] server mac:[u'hmac-md5', u'hmac-sha1', u'[email protected]', u'hmac-sha2-256', u'hmac-sha2-512', u'hmac-ripemd160', u'[email protected]', u'hmac-sha1-96', u'hmac-md5-96'] client compress:[u'none', u'[email protected]'] server compress:[u'none', u'[email protected]'] client lang:[u''] server lang:[u''] kex follows?False
DEBUG:paramiko.transport:Ciphers agreed: local=aes128-ctr, remote=aes128-ctr
DEBUG:paramiko.transport:using kex diffie-hellman-group14-sha1; server key type ssh-rsa; cipher: local aes128-ctr, remote aes128-ctr; mac: local hmac-sha1, remote hmac-sha1; compression: local none, remote none
DEBUG:paramiko.transport:Switch to new keys ...
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.6/dist-packages/paramiko/client.py", line 307, in connect
look_for_keys, gss_auth, gss_kex, gss_deleg_creds, gss_host)
File "/usr/lib/python2.6/dist-packages/paramiko/client.py", line 456, in _auth
self._agent = Agent()
File "/usr/lib/python2.6/dist-packages/paramiko/agent.py", line 339, in __init__
self._connect(conn)
File "/usr/lib/python2.6/dist-packages/paramiko/agent.py", line 68, in _connect
raise SSHException('could not get keys from ssh-agent')
paramiko.ssh_exception.SSHException: could not get keys from ssh-agent
Answer: I found the issue,
i changed :
ssh.connect("172.XX.YY.ZZ",username="test",password="test")
to:
ssh.connect("172.XX.YY.ZZ",username="test",password="test", allow_agent=False)
apparently the switch to "password authentification" is not fully automatic in
some cases
|
OpenCV & Python : Face Detection using haarcascades is detecting many boxes as eyes.
Question: I am using Haarcascades for detecting faces and eyes. My problem is, its
bounding many boxes as eyes. My syntax is
face_cascade = cv2.CascadeClassifier('haarcascades\haarcascade_frontalface_default.xml')
eye_cascade = cv2.CascadeClassifier('haarcascades\haarcascade_eye.xml')
img = cv2.imread('SAM7.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray,1.2,6)
I am currently using 1.2 and 6. What should be the value of the parameters in
faces(5 line) like scaleFactor, minNeighbors ??
Answer: You really need to play with the parameters and find the ones works fine for
you. Always there is a better way to do it but remember you'll never achieve
100% accuracy. You can learn about the parameters
[here](http://docs.opencv.org/2.4/modules/objdetect/doc/cascade_classification.html#cascadeclassifier-
detectmultiscale).
An example of face and eyes detection in python that works for me:
import cv2
face_cascade = cv2.CascadeClassifier("../haarcascades/haarcascade_frontalface_default.xml")
eye_cascade = cv2.CascadeClassifier("../haarcascades/haarcascade_eye.xml")
cap = cv2.VideoCapture(0)
while cap.isOpened():
ret, frame = cap.read()
if ret:
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(
gray,
scaleFactor=1.3,
minNeighbors=5,
minSize=(50, 50)
)
for (x, y, w, h) in faces:
cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0),2)
roi_gray = gray[y:y + h, x:x + w]
roi_color = frame[y:y + h, x:x + w]
eyes = eye_cascade.detectMultiScale(
roi_gray,
scaleFactor=1.2,
minNeighbors=5,
minSize=(10, 10)
)
for (ex, ey, ew, eh) in eyes:
cv2.rectangle(roi_color, (ex, ey), (ex + ew, ey + eh), (255, 0, 0), 2)
cv2.imshow("Faces found", frame)
k = cv2.waitKey(10) & 0xff
if k == 27:
break
cv2.destroyAllWindows()
cap.release()
I hope this helps you. If you need help with the code let me know.
|
Curl is working but urllib2 fails in python
Question: I am working on Zomato API for my application, when I hit request using curl I
get the correct response but when I try same using urllib2 I get different
answer.
**Curl Request**
import os
def callCurl():
os.popen('curl -X GET --header "Accept: application/json" --header "user_key: key" "https://developers.zomato.com/api/v2.1/geocode?lat=18.5363242&lon=73.8932641" > out.txt')
f = open("out.txt")
text = f.read()
print text
**Output**
{"location":{"entity_type":"","entity_id":0,"title":"Koregaon Park","latitude":"18.5363242000","longitude":"73.8932641000","city_id":5,"city_name":"Pune","country_id":1,"country_name":"India"},"popularity":{"popularity":"4.88","nightlife_index":"4.92","nearby_res":["11135","6504409","10750","10987","11520","10143","10699","10213","10580"],"top_cuisines":["North Indian","Fast Food","Italian","Desserts","Chinese"],"popularity_res":"100","nightlife_res":"10","subzone":"Koregaon Park","subzone_id":3307,"city":"Pune"},"link":"https:\/\/www.zomato.com\/pune\/koregaon-park-restaurants?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","nearby_restaurants":{"1":{"restaurant":{"R":{"res_id":11135},"apikey":"key","id":"11135","name":"Uncle's Chinese","url":"https:\/\/www.zomato.com\/pune\/uncles-chinese-koregaon-park?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","location":{"address":"3 & 5, A\/10, Meera Garden Society, Lane 7, Off North Main Road, Koregaon Park, Pune","locality":"Koregaon Park","city":"Pune","city_id":5,"latitude":"18.5374166667","longitude":"73.9000250000","zipcode":"0","country_id":1},"cuisines":"Chinese, Thai","average_cost_for_two":550,"price_range":2,"currency":"Rs.","offers":[],"thumb":"https:\/\/b.zmtcdn.com\/data\/pictures\/chains\/5\/11135\/3450ffa45030801aa2f4934fe77b280e_featured_thumb.jpg","user_rating":{"aggregate_rating":"3.7","rating_text":"Very Good","rating_color":"5BA829","votes":638},"photos_url":"https:\/\/www.zomato.com\/pune\/uncles-chinese-koregaon-park\/photos#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","menu_url":"https:\/\/www.zomato.com\/pune\/uncles-chinese-koregaon-park\/menu#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","featured_image":"https:\/\/b.zmtcdn.com\/data\/pictures\/5\/11135\/db4bce431acbbe60afba5a6e8b39719e_featured_v2.jpg","has_online_delivery":1,"is_delivering_now":1,"deeplink":"zomato:\/\/r\/11135","order_url":"https:\/\/www.zomato.com\/pune\/uncles-chinese-koregaon-park\/order?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","order_deeplink":"","events_url":"https:\/\/www.zomato.com\/pune\/uncles-chinese-koregaon-park\/events#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1"}},"2":{"restaurant":{"R":{"res_id":6504409},"apikey":"key","id":"6504409","name":"Effingut Brewerkz","url":"https:\/\/www.zomato.com\/pune\/effingut-brewerkz-koregaon-park?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","location":{"address":"21\/A , Plot 389, Lane Number 6, Serene Bay, Koregaon Park, Pune 411001","locality":"Koregaon Park","city":"Pune","city_id":5,"latitude":"18.5342194444","longitude":"73.8984916667","zipcode":"411001","country_id":1},"cuisines":"Continental, North Indian, Mughlai, Burmese","average_cost_for_two":2000,"price_range":4,"currency":"Rs.","offers":[],"zomato_events":[{"event":{"event_id":46679,"start_date":"2016-02-18","end_date":"2016-02-18","end_time":"23:00:00","start_time":"20:00:00","is_active":1,"date_added":"2015-09-10 15:58:04","photos":[{"photo":{"url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/1af\/d672fcb7f03e257ad51006d2a38781af_1441880884.jpg","thumb_url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/1af\/d672fcb7f03e257ad51006d2a38781af_1441880884_thumb.jpg","order":0,"md5sum":"d672fcb7f03e257ad51006d2a38781af","photo_id":88657,"uuid":1441880565992433,"type":"NORMAL"}}],"restaurants":[],"is_valid":1,"share_url":"http:\/\/www.zoma.to\/r\/6504409","title":"Pub Quiz - Every Thursday","description":"#ThirstyThursday is back! Answer simple questions and win Effingut beer! Questions on Sports, sitcoms, movies, food, drinks and a lot more! \r\nHow thirsty are you this Thursday? ;)","display_time":"08:00 pm - 11:00 pm","display_date":"18 February","is_end_time_set":1,"disclaimer":"Restaurants are solely responsible for the service; availability and quality of the events including all or any cancellations\/ modifications\/ complaints.","event_category":0,"event_category_name":"","book_link":""}}],"thumb":"https:\/\/b.zmtcdn.com\/data\/pictures\/9\/6504409\/ab9ffd804fa06c820ee0aba93161e9b9_res_featured_thumb.jpg","user_rating":{"aggregate_rating":"4.4","rating_text":"Excellent","rating_color":"3F7E00","votes":829},"photos_url":"https:\/\/www.zomato.com\/pune\/effingut-brewerkz-koregaon-park\/photos#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","menu_url":"https:\/\/www.zomato.com\/pune\/effingut-brewerkz-koregaon-park\/menu#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","featured_image":"https:\/\/b.zmtcdn.com\/data\/pictures\/9\/6504409\/ab9ffd804fa06c820ee0aba93161e9b9_featured_v2.jpg","has_online_delivery":1,"is_delivering_now":0,"deeplink":"zomato:\/\/r\/6504409","events_url":"https:\/\/www.zomato.com\/pune\/effingut-brewerkz-koregaon-park\/events#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1"}},"3":{"restaurant":{"R":{"res_id":10750},"apikey":"key","id":"10750","name":"Dario's","url":"https:\/\/www.zomato.com\/pune\/darios-koregaon-park?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","location":{"address":"Sundarban Hotel, Lane 1, Off North Main Road, Koregaon Park, Pune","locality":"Koregaon Park","city":"Pune","city_id":5,"latitude":"18.5375833333","longitude":"73.8885194444","zipcode":"0","country_id":1},"cuisines":"Italian, Cafe, Salad, Healthy Food","average_cost_for_two":1800,"price_range":3,"currency":"Rs.","offers":[],"thumb":"https:\/\/b.zmtcdn.com\/data\/pictures\/0\/10750\/05965fda1b86a06071c8312b33466ca0_res_featured_thumb.jpg","user_rating":{"aggregate_rating":"4.3","rating_text":"Excellent","rating_color":"3F7E00","votes":1761},"photos_url":"https:\/\/www.zomato.com\/pune\/darios-koregaon-park\/photos#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","menu_url":"https:\/\/www.zomato.com\/pune\/darios-koregaon-park\/menu#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","featured_image":"https:\/\/b.zmtcdn.com\/data\/pictures\/0\/10750\/05965fda1b86a06071c8312b33466ca0_featured_v2.jpg","has_online_delivery":1,"is_delivering_now":1,"deeplink":"zomato:\/\/r\/10750","order_url":"https:\/\/www.zomato.com\/pune\/darios-koregaon-park\/order?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","order_deeplink":"","events_url":"https:\/\/www.zomato.com\/pune\/darios-koregaon-park\/events#tabtop?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1"}},"4":{"restaurant":{"R":{"res_id":10987},"apikey":"key","id":"10987","name":"Cafe 1730","url":"https:\/\/www.zomato.com\/pune\/cafe-1730-koregaon-park?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","location":{"address":"21\/1, Serene Bay, Lane 6, Off North Main Road, Koregaon Park, Pune","locality":"Koregaon Park","city":"Pune","city_id":5,"latitude":"18.5341833333","longitude":"73.8982777778","zipcode":"0","country_id":1},"cuisines":"European, Continental, North Indian, Goan, Cafe","average_cost_for_two":2000,"price_range":4,"currency":"Rs.","offers":[],"zomato_events":[{"event":{"event_id":55453,"start_date":"2016-01-02","end_date":"2016-02-29","end_time":"21:00:00","start_time":"11:00:00","is_active":1,"date_added":"2016-01-02 13:14:33","photos":[{"photo":{"url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/9e2\/e210d91c583b9aeafa90930e7134b9e2_1455112161.jpg","thumb_url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/9e2\/e210d91c583b9aeafa90930e7134b9e2_1455112161_thumb.jpg","order":0,"md5sum":"e210d91c583b9aeafa90930e7134b9e2","photo_id":107008,"uuid":14551121586638,"type":"FEATURED"}},{"photo":{"url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/404\/7500c47cc5571bf24c115a8a64273404_1448960204.jpg","thumb_url":"https:\/\/b.zmtcdn.com\/data\/zomato_events\/photos\/404\/7500c47cc5571bf24c115a8a64273404_1448960204_thumb.jpg","order":1,"md5sum":"7500c47cc5571bf24c115a8a64273404","photo_id":102274,"uuid":14517206735387,"type":"NORMAL"}}],"restaurants":[],"is_valid":1,"share_url":"http:\/\/www.zoma.to\/r\/10987","title":"Steal The Bar","description":"-PITCHERS-\r\n*Its Not A Beer 999\/-\r\n*Lemon Tarika 999\/-\r\n*Sweet Lime & Jalapeno 999\/-\r\n*Pink Panthers 1399\/-\r\n*The Idol Eyes 1399\/-\r\n*1730 Jubilee 1199\/-\r\n*Long Island Iced Tea 1399\/-\r\n*Cosmopolitan 1099\/-\r\n*Mojito 1199\/-\r\n*Apple Sangria 1099\/-\r\n*Fresh Lime Martini 1099\/-\r\n\r\n-BAR DEALS-\r\n*Beer glass 79\/-\r\n*Beer Tower 669\/-\r\n*Kingfisher beer bucket 599\/-\r\n*K.f. ultra bucket 749\/-\r\n*Domestic whisky 675\/-\r\n(Blenders pride\/antiquity blue\/signature premium 3.60ml)\r\n*Bacardi \/vodka 699\/-\r\n(3.60ml)\r\n*Dark rum 399\/-\r\n(3.60ml)\r\n*Regular scotch 999\/-\r\n(Teachers highland cream\/teachers50\/vat69\/ballantines)\r\n(3.60ml)\r\n*Premium vodka 1399\/-\r\n(Absolut flavors \/ absolut \/ketelone)3.60ml","display_time":"11:00 am - 09:00 pm","display_date":"02 January - 29 February","is_end_time_set":1,"disclaimer":"Restaurants are solely responsible for the service; availability and quality of the events including all or any cancellations\/ modifications\/ complaints.","event_category":0,"event_category_name":"","book_link":""}},{"event":{"event_id":57508,"start_date":"2016-01-28","end_date":"2016-02-29","end_time":"15:30:59","start_time":"11:00:59","is_active":1,"date_added":"2016-01-28 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But there is more, The al a carte brunch menu offers a definite selection of seasonally inspired brunch dishes. 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**urllib2 Request**
import urllib
import urllib2
import json
def callUrllib():
values = {"lat" : "18.5363242", "lon":"73.8932641"}
headers = {'Accept': 'application/json', 'user_key' : "key"}
data = urllib.urlencode(values)
req = urllib2.Request("https://developers.zomato.com/api/v2.1/geocode", data, headers)
response = urllib2.urlopen(req)
the_page = response.read()
print json.loads(the_page)
**Output**
{"location":{"entity_type":"","entity_id":0,"title":"Koregaon Park","latitude":"18.5363242000","longitude":"73.8932641000","city_id":5,"city_name":"Pune","country_id":1,"country_name":"India"},"popularity":{"status":"failed","message":"Coordinates missing","nightlife_index":0,"popularity":0},"link":"https:\/\/www.zomato.com\/pune\/koregaon-park-restaurants?utm_source=api_basic_user&utm_medium=api&utm_campaign=v2.1","nearby_restaurants":[]}
Using urllib2 I am not getting value for key **nearby_restaurants**. Why both
are giving different output? Am I doing it correctly? Please Help :)
Answer: You are actually doing here `POST` request with python. That's why your
latitude longitude is not accepted by the server as they were sending as
`POST`. If you use NULL value for the `data` it would return same I believe.
To achieve `GET` use following. Here I am adding the data with the url as GET
and sending empty value for second parameter.
req = urllib2.Request("https://developers.zomato.com/api/v2.1/geocode?"+data, '', headers)
|
Pass a file list from PowerShell to Python script via stdin
Question: I'd like to create a Python script that I can pipe file names into, so it can
be used like this:
ls *.csv | python .\myscript.py
I know I can read the standard input using `fileinput` or `sys.stdin`, but
since the output is in a formatted table:
Directory: C:\path\to\csv
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 15.02.2016 10:18 4755 data_1.csv
-a---- 15.02.2016 10:18 522 data_2.csv
I'd have to parse it.
Since this seems to be a common pattern, I expect there's a standard solution.
I'd like to avoid writing my own if I can, but I haven't been able to find
any.
(In case it's important, I'm running it in PowerShell on Windows 10.)
**Edit:** I'm asking whether there's some library or pattern I'm missing, for
this specific (and seemingly quite common) scenario of piping file paths to a
script. I'd like to avoid writing parsing code if it isn't necessary.
Answer: Based on googling and your kind comments, it seems it would be best to just do
the filtering _before_ passing it to the actual Python script. I'll stick with
that, then.
|
What is the name for the Maya Python library(ies)?
Question: I want to distinguish between the [Python libraries available in
Maya](http://help.autodesk.com/view/MAYAUL/2016/ENU/?guid=GUID-C0F27A50-3DD6-454C-A4D1-9E3C44B3C990):
1. _MEL_ (the embedded Maya language)
2. _Maya Python libraries_ (`maya.cmds`, but also `maya.standalone` and `maya.mel.eval`)
3. _PyMEL_ [[*]](https://github.com/LumaPictures/pymel) (`pymel.core` and others)
4. _Maya Python API 1.0_ (`maya.OpenMaya`)
5. _Maya Python API 2.0_ (`maya.api.OpenMaya`)
Do the Maya Python libraries (item 2) have a name? A name that covers 2, 4 and
5 would be sufficient.
Answer: Not really. `import Maya` will give you all of them, though most people start
one level down with, for example, `import maya.cmds as cmds` There are a few
more that you missed in your list: `OpenMaya` , the old api, has siblings
`OpenMayaRender`, `OpenMayaUI`, and `OpenMayaAnimation` and there's also
`maya.util`
You can list the full roster of top-level maya modules like this:
import maya
import inspect
maya_modules = {name:mod for name, mod in inspect.getmembers(maya) if inspect.ismodule(mod) }
the full list in Maya 2016 is:
'OpenMaya': <module 'maya.OpenMaya' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMaya.pyc'>,
'OpenMayaAnim': <module 'maya.OpenMayaAnim' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMayaAnim.pyc'>,
'OpenMayaFX': <module 'maya.OpenMayaFX' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMayaFX.pyc'>,
'OpenMayaMPx': <module 'maya.OpenMayaMPx' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMayaMPx.pyc'>,
'OpenMayaRender': <module 'maya.OpenMayaRender' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMayaRender.pyc'>,
'OpenMayaUI': <module 'maya.OpenMayaUI' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\OpenMayaUI.pyc'>,
'app': <module 'maya.app' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\app\__init__.py'>,
'cmds': <module 'maya.cmds' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\cmds\__init__.py'>,
'debug': <module 'maya.debug' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\debug\__init__.py'>,
'mel': <module 'maya.mel' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\mel\__init__.py'>,
'standalone': <module 'maya.standalone' (built-in)>,
'utils': <module 'maya.utils' from 'c:\program files\autodesk\maya2016\Python\lib\site-packages\maya\utils.py'>
It would of course be trivial to make your own module which imported a subset
of those.
|
Python - How to get the filename in tkinter file dialog
Question: I am trying to get just the file name of the selected file in tkinter file
dialog
Here's my code:
def browseFile(self):
root = tk.Tk()
root.withdraw()
file_path = askopenfilename(filetypes=(("Video files", "*.mp4;*.flv;*.avi;*.mkv"),
("All files", "*.*") ))
print file_path
What I am getting with this code is the whole path of the selected file, where
I only need the file name. How can I do it?
results with my code:
C:/Users/Guest/vid1.mp4
what I want:
vid1.mp4
Answer:
>>> import os
>>> s = "C:/Users/Guest/vid1.mp4"
>>> os.path.split(s)
('C:/Users/Guest', 'vid1.mp4')
>>> os.path.split(s)[1]
'vid1.mp4'
Alternatively,
>>> os.path.basename(s)
'vid1.mp4'
|
Python if, elif, else chain alternitive
Question: I am using a speech recognition library to create a Siri like program. I hope
that in the future I can use the code with an Arduino to control things around
my room. Here is my problem:
I have the basic speech recognition code worked out but for the program to
understand certain commands I would have to run the speech through a very long
list of if-elif-elif-elif-else commands and that might be slow. As most of the
time it will be resulting at else as the command will not be recognized I need
a faster alternative to a long chain of if-elif-else statements. I am also
using a tts engine to talk back to you.
here is my code so far
import pyttsx
import time
engine = pyttsx.init()
voices = engine.getProperty("voices")
spch = "There is nothing for me to say"
userSaid = "NULL"
engine.setProperty("rate", 130)
engine.setProperty("voice", voices[0].id)
def speak():
engine.say(spch)
engine.runAndWait()
def command():
**IF STATEMENT HERE**
r = sr.Recognizer()
with sr.Microphone() as source:
r.adjust_for_ambient_noise(source)
print("CaSPAR is calibrated")
audio = r.listen(source)
try:
userSaid = r.recognize_google(audio)
except sr.UnknownValueError:
spch = "Sorry, I did'nt hear that properly"
except sr.RequestError as e:
spch = "I cannot reach the speech recognition service"
speak()
print "Done"
Answer: Try using a dictionary setting in which the key is the value that you are
testing for and the entry for that key is a function to process. Some of the
text books on Python point out that this is a more elegant solution than a
series of if ... elif statements and picks up the entry immediately instead of
having to test each possibility. Note that since each key can be of any type,
this is better than something like the switch statement in C which requires
the switch argument and the cases to be integer values. For example.
def default(command)
print command, ' is an invalid entry'
mydict = {'create':mycreate, 'delete':mydelete, 'update':myupdate}
action = mydict.get(command, default)
# set up args from the dictionary or as command for the default.
action(*args)
An interesting point is that [Most efficient way of making an if-elif-elif-
else statement when the else is done the
most?](http://stackoverflow.com/questions/17166074/most-efficient-way-of-
making-an-if-elif-elif-else-statement-when-the-else-is-don) states that while
the get is more "elegant" it may actually be slower than the code below.
However, that may be because the post deals with direct operations and not
function calls. YMMV
def default(command)
print command, ' is an invalid entry'
mydict = {'create':mycreate, 'delete':mydelete, 'update':myupdate}
if command in mydict:
action = mydict.[command]
# set up args from the dictionary .
action(*args)
else:
default(command)
|
Python Domain Name Regular Expression Pattern
Question: I would like to be able to match a domain by following the below rules:
* The domain name should be a-z | A-Z | 0-9 and hyphen(-)
* The domain name should between 1 and 63 characters long
* Last Tld must be at least two characters, and a maximum of 6 characters
* The domain name should not start or end with hyphen (-) (e.g. -google.com or google-.com)
* The domain name can be a subdomain (e.g. mkyong.blogspot.com)
I already have the java flavored regex I just need this python flavored
^((?!-)[A-Za-z0-9-]{1,63}(?<!-)\\.)+[A-Za-z]{2,6}$
I couldn't find any python regex for this matter as everyone expects the use
of urlparse. I don't need to split a url by domain, port, tlds and so on, I
only need to do a simple domain replace so regex should be the solution for me
What I have done:
expectedstring = re.sub(r"^((?!-)[A-Za-z0-9-]{1,63}(?<!-)\\.)+[A-Za-z]{2,6}$" , "XXX" , string)
Example strings:
string = "This is why this domain example.com will never be the same after some years, it might just be example.co.uk but will never get to example.-com. Documents could be located in this specific location http://en.example.com/documents/print.doc as you probably already know."
expectedstring = "This is why this domain XXX will never be the same after some years, it might just be XXX but will never get to example.-com. Documents could be located in this specific location http://XXX/documents/print.doc as you probably already know."
List of valid domain names
* www.google.com
* google.com
* mkyong123.com
* mkyong-info.com
* sub.mkyong.com
* sub.mkyong-info.com
* mkyong.com.au
* g.co
* mkyong.t.t.co
List of invalid domain names, and why.
* mkyong.t.t.c - Tld must between 2 and 6 long
* mkyong,com - Comma is not allow
* mkyong - No Tld
* mkyong.123 , Tld not allow digit
* .com - Must start with [A-Za-z0-9]
* mkyong.com/users - No Tld
* mkyong.com - Cannot begin with a hyphen -
* mkyong-.com - Cannot end with a hyphen -
* sub.-mkyong.com - Cannot begin with a hyphen -
* sub.mkyong-.com - Cannot end with a hyphen -
Answer: I run a test based on the list of given domain names (python 2.7x):
import re
valid_domains = """
www.google.com
google.com
mkyong123.com
mkyong-info.com
sub.mkyong.com
sub.mkyong-info.com
mkyong.com.au
g.co
mkyong.t.t.co
"""
invalid_domains = """
mkyong.t.t.c
mkyong,com
mkyong
mkyong.123
.com
mkyong.com/users
-mkyong.com
mkyong-.com
sub.-mkyong.com
sub.mkyong-.com
"""
valid_names = valid_domains.split()
invalid_names = invalid_domains.split()
# match 1 character domain name or 2+ domain name
pattern = '^([A-Za-z0-9]\.|[A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9]\.){1,3}[A-Za-z]{2,6}$'
print 'checking valid domain names ============'
for name in valid_names:
print name.ljust(50), ('True' if re.match(pattern, name) else 'False').rjust(5)
print '\nchecking invalid domain names ============'
for name in invalid_names:
print name.ljust(50), ('True' if re.match(pattern, name) else 'False').rjust(5)
Output:
checking valid domain names ============
www.google.com True
google.com True
mkyong123.com True
mkyong-info.com True
sub.mkyong.com True
sub.mkyong-info.com True
mkyong.com.au True
g.co True
mkyong.t.t.co True
checking invalid domain names ============
mkyong.t.t.c False
mkyong,com False
mkyong False
mkyong.123 False
.com False
mkyong.com/users False
-mkyong.com False
mkyong-.com False
sub.-mkyong.com False
sub.mkyong-.com False
[Edit] To achieve the same result as the expectedstring provided, I come up
with the following approach (without checking "http(s)")οΌ
import re
# match 1 character domain name or 2+ domain name
pattern = '(//|\s+|^)(\w\.|\w[A-Za-z0-9-]{0,61}\w\.){1,3}[A-Za-z]{2,6}'
string = "This is why this domain example.com will never be the same after some years, it might just be example.co.uk but will never get to example.-com. Documents could be located in this specific location http://en.example.com/documents/print.doc as you probably already know."
expectedstring = "This is why this domain XXX will never be the same after some years, it might just be XXX but will never get to example.-com. Documents could be located in this specific location http://XXX/documents/print.doc as you probably already know."
resultstring = ''.join([re.sub(pattern , "\g<1>XXX" , string)])
print 'resultstring: \n', resultstring
print '\nare they equal? ', expectedstring == resultstring
Output is:
resultstring:
This is why this domain XXX will never be the same after some years, it might just be XXX but will never get to example.-com. Documents could be located in this specific location http://XXX/documents/print.doc as you probably already know.
are they equal? True
|
How to obtain a math function as an output in python
Question: I want to do something like this
def gaussian(x, amp):
return amp * exp(-(x-cen)**2 /wid)
I want to substitute just amp and x and obtain an equation as output
for example:
gaussian(1,3)
`3 * exp(-(1-cen)**2 /wid)` as output.
Can I do this for a couple of lists, in one several values of amplitude an in
the other their respective x's
Answer: I am not sure what you mean by "I need an equation". Do you need something you
can evaluate? Then probably you can return a lambda object, and then you can
evaluate that. Or you can use closure something like:
import math
def gaussian(x, amp):
def _gauss( cen,wid):
return amp * math.exp(-(x-cen)**2 /wid)
return _gauss
g = gaussian(10,1)
print g(2,4)
g now is a callable function where x and amp has been replaced so you need to
pass only cen and wid
The reason why this work is because the internal function, _gauss, gets
evaluated every time you call the wrapper function, doing so the function will
be evaluated using the argument passed by the parent function and be used
there as "static". Since then you return a function you can evaluate that and
pass all the params left, this is a common technique for when a library forces
you to have parameterlles callbacks. Only draw back is more expensive then a
simple function call, that is to generate the child function, not to evaluate
it.
|
Logging not working in a separate thread
Question: I've a `python 2.5` app that creates a separate thread to work. I want to log
to a file, and I'm able to do it from the main thread, but when I log from the
other threads it doesnt works.
This happen on the main thread:
log_filename = os.path.join(os.path.dirname(__file__), "log", args[1]+'.log')
logging.basicConfig(filename=log_filename, level=logging.DEBUG)
logging.debug("Hello world!") # this works, line got written to a file
This is how the thread are getting initialized:
worker_thread = threading.Thread(target = MY_worker.MY_worker, args = tuple([task_queue]))
worker_thread.start()
Now from a method that runs on the thread I'm doing:
logging.debug("testing") # this doesnt got printed in the log file
I even tried setting up the log again (inside the thread, just before writting
to log):
log_filename = os.path.join(os.path.dirname(__file__), "log", 'sandbox.log')
logging.basicConfig(filename=log_filename, level=logging.DEBUG)
logging.debug("testing") # doesn't works neither.
I tried writting directly to a file, and it worked:
f = open(log_filename,'a')
f.write('some testing message \n')
f.close()
Why is this happening and how to make it work?
Answer: Are you quite sure it's not some problem unrelated to the logging? The
following trivial script behaves as expected, under both Python 2.x and 3.x.
import logging
import threading
import time
def worker(arg):
while not arg['stop']:
logging.debug('Hi from myfunc')
time.sleep(0.5)
def main():
logging.basicConfig(level=logging.DEBUG, format='%(relativeCreated)6d %(threadName)s %(message)s')
info = {'stop': False}
thread = threading.Thread(target=worker, args=(info,))
thread.start()
while True:
try:
logging.debug('Hello from main')
time.sleep(0.75)
except KeyboardInterrupt:
info['stop'] = True
break
thread.join()
if __name__ == '__main__':
main()
When run, it produces
0 Thread-1 Hi from myfunc
1 MainThread Hello from main
502 Thread-1 Hi from myfunc
753 MainThread Hello from main
1003 Thread-1 Hi from myfunc
1504 Thread-1 Hi from myfunc
1505 MainThread Hello from main
2006 Thread-1 Hi from myfunc
2255 MainThread Hello from main
2507 Thread-1 Hi from myfunc
3007 MainThread Hello from main
3009 Thread-1 Hi from myfunc
3510 Thread-1 Hi from myfunc
3759 MainThread Hello from main
4012 Thread-1 Hi from myfunc
until I stop it with Ctrl-C.
|
Python bindings for VLC
Question: I am on Windows, and I wish to use Python Bindings for VLC. I've already
downloaded the module from <https://github.com/geoffsalmon/vlc-python> , and
did as per the read me. But, still I'm stuck at importing the module. The
error looks like this :
Traceback (most recent call last):
File "<pyshell#5>", line 1, in <module>
import vlc
File "c:\python27\python-vlc-1.1.2\vlc.py", line 173, in <module>
dll, plugin_path = find_lib()
File "c:\python27\python-vlc-1.1.2\vlc.py", line 150, in find_lib
dll = ctypes.CDLL('libvlc.dll')
File "C:\Python27\lib\ctypes\__init__.py", line 353, in __init__
self._handle = _dlopen(self._name, mode)
WindowsError: [Error 126] The specified module could not be found
Any Solution on where to place the module ? My main aim is to play MP3 audio
files through vlc, which would be part of some other activity.
Answer: I had same problem. It turns out for me if you have 64bit python, you need
64bit vlc player. If you have 32bit python, you need 32bit vlc player.
Hope that works for you too.
|
'application not registered on db instance' after user table truncation
Question: I deleted all the info in my users table during testing. Now when I try to run
a `manage.py` command to recreate the admin user, I get `RuntimeError:
application not registered on db instance and no application bound to current
context`. I've been reading about Flask contexts, especially [What is the
purpose of Flask's context
stacks?](http://stackoverflow.com/questions/20036520/what-is-the-purpose-of-
flasks-context-stacks), but it's not clear to me how to fix this. How do I fix
this error?
$ python manage.py db create_admin
Traceback (most recent call last):
File "manage.py", line 58, in <module>
manager.add_command("create_admin", create_admin())
File "manage.py", line 47, in create_admin
confirmed_on=datetime.datetime.now()
File "c:\envs\virtalenvs\flask_mini\lib\site-packages\sqlalchemy\orm\scoping.py", line 150, in do
return getattr(self.registry(), name)(*args, **kwargs)
File "c:\envs\virtalenvs\flask_mini\lib\site-packages\sqlalchemy\util\_collections.py", line 878, in __call__
return self.registry.setdefault(key, self.createfunc())
File "c:\envs\virtalenvs\flask_mini\lib\site-packages\flask_sqlalchemy\__init__.py", line 704, in create_session
return SignallingSession(self, **options)
File "c:\envs\virtalenvs\flask_mini\lib\site-packages\flask_sqlalchemy\__init__.py", line 149, in __init__
self.app = db.get_app()
File "c:\envs\virtalenvs\flask_mini\lib\site-packages\flask_sqlalchemy\__init__.py", line 845, in get_app
raise RuntimeError('application not registered on db '
RuntimeError: application not registered on db instance and no application bound to current context
`manage.py`:
import os
from flask_script import Manager
from myflaskapp.app import create_app
from myflaskapp.models.user import User
from myflaskapp.database import db
manager = Manager(app)
@manager.command
def create_admin():
db.session.add(User(
username="admin1",
email="[email protected]",
password="admin",
admin=True,
confirmed=True,
confirmed_on=datetime.datetime.now()
))
db.session.commit()
manager.add_command("create_admin", create_admin())
manager.run()
Answer: You're using `@manager.command`, so you shouldn't also use
`manager.add_command`. Completely remove the line
`manager.add_command('create_admin', create_admin())`.
If you want to use `add_command`, then remove `@manager.command` and use
`manager.add_command('create_admin', Command(create_admin))`.
You get the error because the app context is only active when the manager is
running, but you're calling the function prematurely.
|
return index for rows in csv module python
Question: I'm trying to return a specific string that reads out "RowX: [sum of row]" for
each row of a tsv table where X = the row number (index +1). So far I can get
everything to work except for the row number.
My code:
#!/usr/bin/env python
from __future__ import division, print_function
import sys
import csv
def my_sum(row):
a = 0
for i in row:
a = a + float(i)
return a
def main():
tsvfile_input = sys.argv[1]
data = csv.reader(open(tsvfile_input), delimiter = '\t')
for row in data:
RowSum = my_sum(row)
print('Row' + 'X' + ': ' + str(RowSum))
if __name__ == '__main__':
main()
So far in place of 'X' I've tried data.index(), which returned:
AttributeError: '_csv.reader' object has no attribute 'index'
Sorry if obvious. I'm extremely new to coding and am doing this as part of an
exercise. Also, if you're wondering why I didn't just use sum(), it's part of
the exercise to not use sum().
Thanks!
Answer: How about
[enumerating](https://docs.python.org/2/library/functions.html#enumerate) the
data?
for index, row in enumerate(data):
RowSum = my_sum(row)
print('Row %d: %f' % (index + 1, rowSum))
Python also has sum function already, so you can do:
for index, row in enumerate(data):
print('Row %d: %f' % (index + 1, sum(float(num) for num in row)))
Edit (full example of the main function):
def main():
tsvfile_input = sys.argv[1]
data = csv.reader(open(tsvfile_input), delimiter = '\t')
for index, row in enumerate(data):
print('Row %d: %f' % (index + 1, sum(float(num) for num in row)))
|
NxN python arrays subsets
Question: I need to carry out some operation on a subset of an `NxN array`. I have the
center of the sub-array, `x` and `y`, and its size.
So I can easily do:
`subset = data[y-size:y+size,x-size:x+size]`
And this is fine.
What I ask is if there is the possibility to do the same without writing an
explicit loop if `x` and `y` are both 1D arrays of positions.
Thanks!
Answer: Using a simple example of a 5x5 array and setting _size=1_ we can get:
import numpy as np
data = np.arange(25).reshape((5,5))
size = 1
x = np.array([1,4])
y = np.array([1,4])
subsets = [data[j-size:j+size,i-size:i+size] for i in x for j in y]
print(subsets)
Which returns a list of numpy arrays:
[array([[0, 1],[5, 6]]),
array([[15, 16],[20, 21]]),
array([[3, 4],[8, 9]]),
array([[18, 19],[23, 24]])]
Which I hope is what you are looking for.
|
Opening a sheet in excel file in Python
Question: I am an absolute beginner in Python programming. I have a bunch of excel files
(with extension .xls) which I would like to be able to read in python. I have
to extract 2 columns from a given sheet from each file and write them into a
CSV file. This is data coming from some measurement results so the format of
each excel file is the same. I have to create n CSV files from a given number
of n excel files.
From my general search I figured I could use module xlrd. I tried downloading
the module as described [here](http://stackoverflow.com/questions/20461790/im-
having-a-lot-of-trouble-installing-xlrd-0-9-2-for-python). I am working on
windows with python 2 and using Python GUI IDLE. When I go to the command line
in windows, browse to the folder where I saved the module files and type
python setup.py build
I get an error message saying "`python is not recognized as an internal or
external command, operable program or batch file`."
I also setup the system variable as described
[here](http://stackoverflow.com/questions/19407469/xlrd-import-issue-with-
python-2-7) but that does not help. As I read somewhere else, I use
import sys
print sys.path
which displays
['', 'C:\\Python27\\Lib\\idlelib', 'C:\\Windows\\system32\\python27.zip', 'C:\\Python27\\DLLs', 'C:\\Python27\\lib', 'C:\\Python27\\lib\\plat-win', 'C:\\Python27\\lib\\lib-tk', 'C:\\Python27', 'C:\\Python27\\lib\\site-packages']
Does that mean my environment variable is correctly set up? Please help me
getting started with using .xls files in Python.
Thanks.
Answer: Solution [here](http://stackoverflow.com/questions/20461790/im-having-a-lot-
of-trouble-installing-xlrd-0-9-2-for-python) proposed by M4rtini worked for
me. Posting here again
If windows this should work. Browser to "folder with python"\scripts Open cmd
here (shift + right click and and it should be an option in the context menu.)
type inn: easy_install.exe xlrd It should download and install if for you
|
Sort Python DataFrame by Day of the Week
Question: I'm trying to sort my dataframe by the day of the week in the index. I was
able to create a workaround where I created an additional column that I
manually assigned the correct order value to and then sorted. But there has to
be a better way, especially when I'm dealing with potentially more date
values.
dict = {'Monday': Monday/MonCount, 'Tuesday': Tuesday/TueCount, 'Wednesday': Wednesday/WedCount, 'Thursday': Thursday/ThuCount, 'Friday': Friday/FriCount}
df = pd.Series(dict, name='DailyValue')
dff = DataFrame(df)
dff['Day'] = dff.index
dff['Sorter'] = [5,1,4,2,3]
dff.sort_values(by = ['Sorter'], inplace = True)
#dff.sort(['Day'], ascending = True)
dff.plot(kind='bar', grid = True, y = ['DailyValue'])
plt.show()
Answer: You can use a list comprehension to generate the weekdays (i.e. 0-6) in your
index, and then create a series from these values. You sort this series by
these weekday values and take the index. You then use `ix` to index your
original series based on this sorted index.
import numpy as np
import pandas as pd
s = pd.Series(np.random.randn(14), index=pd.date_range('2016-1-1', periods=14))
s
Out[34]:
2016-01-01 0.915488
2016-01-02 -1.053409
2016-01-03 -1.826033
2016-01-04 0.559250
2016-01-05 -0.278086
2016-01-06 0.041113
2016-01-07 1.076463
2016-01-08 0.942720
2016-01-09 -0.850388
2016-01-10 -0.649713
2016-01-11 2.769957
2016-01-12 0.498103
2016-01-13 1.098085
2016-01-14 0.699077
Freq: D, dtype: float64
idx = pd.Series([d.weekday() for d in s.index]).sort_values().index
s.ix[idx]
Out[36]:
2016-01-04 0.559250
2016-01-11 2.769957
2016-01-05 -0.278086
2016-01-12 0.498103
2016-01-06 0.041113
2016-01-13 1.098085
2016-01-07 1.076463
2016-01-14 0.699077
2016-01-01 0.915488
2016-01-08 0.942720
2016-01-02 -1.053409
2016-01-09 -0.850388
2016-01-03 -1.826033
2016-01-10 -0.649713
dtype: float64
As a one liner...
s_new = s.ix[pd.Series([d.weekday() for d in s.index]).sort_values().index]
Exactly the same for a dataframe.
df_new = df.ix[pd.Series([d.weekday() for d in df.index]).sort_values().index]
|
Redirecting output of script called from within Flask, into its own log file
Question: One of the user options in my Flask application is to trigger a web-scrape.
The output of this process (and indeed _any_ external process, and the output
of the main Flask app itself) is stdout which is the terminal in which I've
started my main Flask app.
I wish to maintain the overall Flask log in the terminal, while forcing the
log from the scraping process into its own file (for downloading). So given:
@app.route("/download-log", methods=["GET"])
def downloadlog():
# Check for valid file and assign it to `inbound_file`
with open('log.txt', 'r') as log:
contents = log.read()
response = make_response(contents)
response.headers["Content-Disposition"] = "attachment; filename=log.txt"
return response
.. which is working well, I need **log.txt** (currently just a `touch`ed file
for proof-of-concept) to be the log from the scraping process, which I call
thus:
@app.route('/scrape', methods=['GET', 'POST'])
@login_required # Use of @login_required decorator
def scrape():
scraper.scrape('/path/to/URLs.csv', ['manager'])
where `scraper` is a standalone python script that can and does run off its
own bat normally, but is being called from within the Flask app here. I know
how to redirect stdout into a file when calling a script itself, but how can I
get the stdout of scraper.py into a file when it has been invoked from the
Flask app?
Answer: edit scraper.py and add a redirect to a log file:
import sys
sys.stdout = sys.stderr = open('log.txt','wt')
|
google-api-python-client broken because of OAuth2?
Question: I am trying to check if a certain dataset exists in bigquery using the Google
Api Client in Python. It always worked untill the last update where I got this
strange error I don't know how to fix:
Traceback (most recent call last):
File "/root/miniconda/lib/python2.7/site-packages/dsUtils/bq_utils.py", line 106, in _get
resp = bq_service.datasets().get(projectId=self.project_id, datasetId=self.id).execute(num_retries=2)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/util.py", line 140, in positional_wrapper
return wrapped(*args, **kwargs)
File "/root/miniconda/lib/python2.7/site-packages/googleapiclient/http.py", line 755, in execute
method=str(self.method), body=self.body, headers=self.headers)
File "/root/miniconda/lib/python2.7/site-packages/googleapiclient/http.py", line 93, in _retry_request
resp, content = http.request(uri, method, *args, **kwargs)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/client.py", line 598, in new_request
self._refresh(request_orig)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/client.py", line 864, in _refresh
self._do_refresh_request(http_request)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/client.py", line 891, in _do_refresh_request
body = self._generate_refresh_request_body()
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/client.py", line 1597, in _generate_refresh_req
uest_body
assertion = self._generate_assertion()
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/service_account.py", line 263, in _generate_ass
ertion
key_id=self._private_key_id)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/crypt.py", line 97, in make_signed_jwt
signature = signer.sign(signing_input)
File "/root/miniconda/lib/python2.7/site-packages/oauth2client/_pycrypto_crypt.py", line 101, in sign
return PKCS1_v1_5.new(self._key).sign(SHA256.new(message))
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Signature/PKCS1_v1_5.py", line 112, in sign
m = self._key.decrypt(em)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/PublicKey/RSA.py", line 174, in decrypt
return pubkey.pubkey.decrypt(self, ciphertext)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/PublicKey/pubkey.py", line 93, in decrypt
plaintext=self._decrypt(ciphertext)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/PublicKey/RSA.py", line 235, in _decrypt
r = getRandomRange(1, self.key.n-1, randfunc=self._randfunc)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Util/number.py", line 123, in getRandomRange
value = getRandomInteger(bits, randfunc)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Util/number.py", line 104, in getRandomInteger
S = randfunc(N>>3)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Random/_UserFriendlyRNG.py", line 202, in read
return self._singleton.read(bytes)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Random/_UserFriendlyRNG.py", line 178, in read
return _UserFriendlyRNG.read(self, bytes)
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Random/_UserFriendlyRNG.py", line 137, in read
self._check_pid()
File "/root/miniconda/lib/python2.7/site-packages/Crypto/Random/_UserFriendlyRNG.py", line 153, in _check_pid
raise AssertionError("PID check failed. RNG must be re-initialized after fork(). Hint: Try Random.atfork()")
AssertionError: PID check failed. RNG must be re-initialized after fork(). Hint: Try Random.atfork()
Is someone understanding what is hapening?
Note that I also get this error with other bricks like GCStorage.
Note also that I use the following command to load my Google credentials:
from oauth2client.client import GoogleCredentials
def get_credentials(credentials_path): #my json credentials path
logger.info('Getting credentials...')
try:
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = credentials_path
credentials = GoogleCredentials.get_application_default()
return credentials
except Exception as e:
raise e
So if anyone know a better way to load my google credentials using my json
service account file, and which would avoid the error, please tell me.
Answer: It looks like the error is in the PyCrypto module, which appears to be used
under the hood by Google's OAuth2 implementation. If your code is calling
`os.fork()` at some point, you may need to call `Crypto.Random.atfork()`
afterward in both the parent and child process in order to update the module's
internal state.
See here for PyCrypto docs; search for "atfork" for more info:
<https://github.com/dlitz/pycrypto>
This question and answer might also be relevant: [PyCrypto :
AssertionError("PID check failed. RNG must be re-initialized after fork().
Hint: Try
Random.atfork()")](http://stackoverflow.com/questions/16981503/pycrypto-
assertionerrorpid-check-failed-rng-must-be-re-initialized-after-fo)
|
python threading with sync queue
Question: I have a script that follows the same logic in this sample. Basically I insert
items into a global queue and spawn threads with a while loop that gets and
item from the queue and the calls task_done.
I can get the threads to join if my while loop is checking that the queue is
not empty, but I wanted to try and incorporate a flag that I could set myself
to exit the loop. When I try to do this, joining the thread blocks forever.
Here is the non-working sample that doesnt join the threads:
import threading
import queue
class Mythread(threading.Thread):
def __init__(self):
super().__init__()
self.signal = False
def run(self):
global queue
while not self.signal:
item = q.get()
print(item)
q.task_done()
def stop(self):
self.signal = True
q = queue.Queue
for i in range(5000):
q.put(i)
threads = []
for i in range(2):
t = Mythread()
threads.append(t)
for t in threads:
t.start()
q.join()
for t in threads:
print(t.signal) <---- False
t.stop()
print(t.signal) <---- True
t.join() <---- Blocks forever
Here is the one that works using queue empty
import threading
import queue
class Mythread(threading.Thread):
def __init__(self):
super().__init__()
def run(self):
global queue
while not q.empty():
item = q.get()
print(item)
q.task_done()
q = queue.Queue
for i in range(5000):
q.put(i)
threads = []
for i in range(2):
t = Mythread()
threads.append(t)
for t in threads:
t.start()
q.join()
for t in threads:
t.join() <---- Works fine
print(t.is_alive()) <--- returns False
Any ideas?
Answer: q.get blocks so it won't reach your while condition
|
How can I find out what package that a python module belongs to?
Question: You are given some python source code with some import statements for modules
that you don't recognize. You are curious and would like to know what packages
these modules belong to.
2 scenarios.
**Scenario #1:**
Some of the imports fail because you don't have the correct packages
installed.
You need figure out which package to install.
Is there a way to do this without leaving the command line?
**Scenario #2:**
It seems that you do have the modules installed already, but you are curious
about which package they belong to.
Is there a way to discover this quickly and efficiently on the command line?
Answer: Normally a module from a package should be imported as:
import a.b
where **a** is the package and **b** is the module.
So the import statement should tell you what you need.
|
Removing points stored in a dictionary in a matplotlib basemap animation
Question: I am trying to do the following: Plot points and store a reference in a
dictionary. While animating remove points. A minimal example looks as follows:
%matplotlib qt
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib.animation as animation
fig = plt.figure()
m = Basemap(projection='aeqd',lat_0=72,lon_0=29, resolution='l',
llcrnrlon=15, llcrnrlat=69,
urcrnrlon=41, urcrnrlat=75.6,area_thresh = 100)
pointDict=dict()
pointDict[1]=m.plot (0, 0,marker='.',label='first')[0]
pointDict[2]=m.plot (0, 0,marker='.',label='second')[0]
def init():
print ("Init")
x,y = m(30, 73)
pointDict[1].set_data(x,y)
x,y = m(31, 73)
pointDict[2].set_data(x,y)
return pointDict.values()
def animate(i):
print ("Frame {0}".format(i))
if i==2:
l=pointDict.pop(1)
print ("Removing {0}".format(l.get_label()))
l.remove()
del l
return pointDict.values()
anim = animation.FuncAnimation(plt.gcf(), animate, init_func=init,
frames=10, interval=1000, blit=True)
plt.show()
Output:
Init
Init
Frame 0
Frame 1
Frame 2
Removing first
Frame 3
Interestingly, if I am plotting just the first point (that is, remove
pointDict[2]=m.plot and pointDict[2].set_data in the init function), this
works. But if both are plotted, neither removing the first, nor the second
point works.
Related questions brought me just as far as I am now:
[Matplotlib Basemap
animation](http://stackoverflow.com/questions/21207513/matplotlib-basemap-
animation)
[How to remove lines in a Matplotlib
plot](http://stackoverflow.com/questions/4981815/how-to-remove-lines-in-a-
matplotlib-plot)
[Matplotlib animating multiple lines and
text](http://stackoverflow.com/questions/20624408/matplotlib-animating-
multiple-lines-and-text)
[Python, Matplotlib, plot multi-lines (array) and
animation](http://stackoverflow.com/questions/19519587/python-matplotlib-plot-
multi-lines-array-and-animation)
I am using Anaconda with Python-2.7 kernel.
Answer: I found out what the problem is and want therefore to answer my question by
myself: The problem with this is somewhat unexpected the blit=True. Obviously,
blitting can be only used if the point is set within the animate function.
Thus, setting the data in the init routine causes problems. So there are two
options: set blit to False, but this is not very elegant. The other option is
to set the points in the first frame. Then the init and animate functions that
work are as follows:
def init():
print ("Init")
pointDict[1].set_data([],[])
pointDict[2].set_data([],[])
return pointDict.values()
def animate(i):
print ("Frame {0}".format(i))
if i==0:
print ("Init")
x,y = m(30, 73)
pointDict[1].set_data(x,y)
x,y = m(31, 73)
pointDict[2].set_data(x,y)
if i==2:
l=pointDict.pop(1)
print ("Removing {0}".format(l.get_label()))
l.remove()
del l
return pointDict.values()
anim = animation.FuncAnimation(plt.gcf(), animate, init_func=init,
frames=10, interval=1000, blit=True)
plt.show()
|
getMouse in python using graphics
Question: I am very new to Python. I need to write a program to move my ball or circle
when I click the mouse. How do I achieve this? I have the below code that I
got started with.
from graphics import *
import time def MouseTracker():
win = GraphWin("MyWindow", 500, 500)
win.setBackground("blue")
cir = Circle(Point(250,250) ,20)
cir.setFill("red")
cir.draw(win)
while(win.getMouse() != None):
xincr = 0
yincr = 0
for i in range(7):
cir.move(xincr, yincr)
time.sleep(.2)
win.getMouse()
Answer: Assuming you are not bound to some specific tools or implementation, you may
find matplotlib useful. You can plot a circle onto the drawing area using a
circle patch (<http://matplotlib.org/api/patches_api.html>) and then move it
around when there is mouse-click in the graph axes. You will need to connect
to the event-click listener and define a callback function which handles the
drawing update - see <http://matplotlib.org/users/event_handling.html> for
examples of how to do this. You can get the coordinates of the mouse press
using the xdata and ydata methods.
This worked for me in python 2.7:
import matplotlib.pyplot as plt
from matplotlib.patches import Circle
fig = plt.figure()
ax = fig.add_subplot(111)
circ = Circle((0.5,0.5), 0.1)
ax.add_patch(circ)
def update_circle(event):
ax.cla()
circ = Circle((event.xdata, event.ydata), 0.1)
ax.add_patch(circ)
fig.canvas.draw()
fig.canvas.mpl_connect('button_press_event', update_circle)
plt.show()
|
Retain top-N elements as we loop across all elements
Question: Here is what I am trying to do. The output of a calculation on a dataframe
gives a number. I use that number to rank the different dataframes and I need
to retain the top-N (in the example below, the top 10 is chosen). The ranking
is achieved by comparing the number to the last number of a reverse sorted
list. If the current number is larger, the list is popped and the new entry
added to the list followed by reverse sorting again. The following is
structurally identical to what I have and it works, albeit slowly. I would
appreciate any suggestions to improve its speed, efficiency or Pythonicness.
import random
import pandas as pd
def gen_df():
return random.uniform(0.0, 1.0), pd.DataFrame()
if __name__ == '__main__':
mylist = []
for i in range(1000):
val, df = gen_df()
if len(mylist) < 10:
mylist.append((val, df))
else:
mylist.sort(reverse=True)
if mylist[-1][0] < val:
mylist.pop()
mylist.append((val, df))
EDIT: Reduced one sort after suggestion by zondo.
Answer: The way to speed it up is to replace your list with a min-heap of size 10. Put
the first 10 frames into the heap. Then, for each item, if it's larger than
the smallest item on the heap, pop the smallest item and push the new item.
I'm not a Python programmer, so I'll present the pseudocode.
heap = new min-heap
for each item
if (heap.length < 10)
heap.push(item)
else if (item > heap.peek())
heap.pop(); // remove smallest item
heap.push(item); // add new item
This assumes, of course, that there's a min-heap implementation that you can
use. I suspect [heapq](https://docs.python.org/2/library/heapq.html) will do
the trick.
That's going to be significantly faster than sorting the list every time you
insert a new item.
|
Django staticfiles not found on Heroku (with whitenoise)
Question: This question seems to be asked several time but I can not fix it.
I deployed a django app on production with `DEBUG = False`. I set my
`allowed_host`. I used `{% load static from staticfiles %}` to load static
files. I exactly write the settings sugested by Heroku doc :
BASE_DIR = os.path.dirname(os.path.dirname(__file__))
PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))
STATIC_ROOT = os.path.join(PROJECT_ROOT, 'staticfiles')
STATIC_URL = '/static/'
STATICFILES_DIRS = (
os.path.join(PROJECT_ROOT, 'static'),
)
STATICFILES_STORAGE = 'whitenoise.django.GzipManifestStaticFilesStorage'
BUT I got an error 500. And got this traceback (by mail)
...
`cache_name = self.clean_name(self.hashed_name(name))
File "/app/.heroku/python/lib/python3.5/site- packages/django/contrib/staticfiles/storage.py", line 94, in hashed_name (clean_name, self))
...
ValueError: The file βapp/css/font.cssβ could not be found with <whitenoise.django.GzipManifestStaticFilesStorage object at 0x7febf600a7f0>.`
When I run `heroku run python manage.py collectstatic --noinput` All seems ok
:
`276 static files copied to '/app/annuaire/staticfiles', 276 post-processed.`
Does anyone have an idea to help me, please ?
Thanks
EDIT :
annuaire
|-- /annuaire
|-- -- /settings.py
|-- /app
|-- -- /static/...`
wsgi.py
from django.core.wsgi import get_wsgi_application
from whitenoise.django import DjangoWhiteNoise
application = get_wsgi_application()
application = DjangoWhiteNoise(application)
Answer: I got it. I needed to add python manage.py collectstatic --noinput; in my
Procfile. Heroku doc said that `collecticstatic` is automatically triggered.
<https://devcenter.heroku.com/articles/django-assets>
Thanks
|
Is there a way in Python to exit the program if the line is blank?
Question: My file is a .txt file and all comments have no spaces before them.
I have a file with 10,000 lines that looks like this and I am reading every
line of the file.
## something
## something
## something
12312312
123123
12312312
123123
123123
However, my code will fail if there is not a value in every line.
Is there a way in Python to exit the program if the line is blank?
I just need a simple If statement to fix my program.
Something like
if line == blank:
quit
Answer: If you want to completely exit the program and the line contains no
whitespace(if it does replace `line` with `line.strip()`:
if not line:
sys.exit()
assuming you have imported sys
As pointed out by @zondo, you could just use a `continue` statement to skip
that line if you do not want the program to fail:
if not line.strip():
continue
|
malt parser gives assertion error when using it with nltk
Question: I am using malt parser with python nltk. I have successfully downloaded the
training data and updated the latest nltk. When I call the malt parser it
gives me an asertion error. Below is the code from python which includes the
traceback as well.
mp = MaltParser("C:/Users/mustufain/Desktop/Python Files/maltparser-1.8.1","C:/Users/mustufain/Desktop/Python Files/maltparser-1.7.2",additional_java_args=['-Xmx512m'])
Traceback (most recent call last):
File "<pyshell#10>", line 1, in <module>
mp = MaltParser("C:/Users/mustufain/Desktop/Python Files/maltparser-1.8.1","C:/Users/mustufain/Desktop/Python Files/maltparser-1.7.2",additional_java_args=['-Xmx512m'])
File "C:\Python34\lib\site-packages\nltk\parse\malt.py", line 131, in __init__
self.malt_jars = find_maltparser(parser_dirname)
File "C:\Python34\lib\site-packages\nltk\parse\malt.py", line 72, in find_maltparser
assert malt_dependencies.issubset(_jars)
AssertionError
>>>
Answer: **`TL;DR`** (In **PYTHON3**!!):
import urllib.request
urllib.request.urlretrieve('http://www.maltparser.org/mco/english_parser/engmalt.poly-1.7.mco', 'C:\\Users\\mustufain\\Desktop\\engmalt.poly-1.7.mco')
urllib.request.urlretrieve('http://maltparser.org/dist/maltparser-1.8.1.zip', 'C:\\Users\\mustufain\\Desktop\\maltparser-1.8.1.zip')
zfile = zipfile.ZipFile('C:\\Users\\mustufain\\Desktop\\maltparser-1.8.1.zip')
zfile.extractall('C:\\Users\\mustufain\\Desktop\\maltparser-1.8.1\\')
Then:
from nltk.parse import malt
mp = malt.MaltParser('C:\\Users\\mustufain\\Desktop\\maltparser-1.8.1\\', "C:\\Users\\mustufain\\Desktop\\engmalt.poly-1.7.mco")
mp.parse_one('I shot an elephant in my pajamas .'.split()).tree()
|
Python 2.7 imports module from wrong location
Question: I'm on Python 2.7.6 un Ubuntu 14.04 and I'm trying to import openpyxl. I
upraged to a recent version via `sudo pip install openpyxl --upgrade` and `pip
show openpyxl` gives the following output:
pip show openpyxl
---
Name: openpyxl
Version: 2.3.3
Location: /usr/local/lib/python2.7/dist-packages
Requires:
However, when inside python, after I `import openpyxl` It seems to load it
from a different location: `/usr/lib` instead of `/usr/local/lib`
openpyxl.__version__
'1.7.0'
openpyxl.__file__
'/usr/lib/pymodules/python2.7/openpyxl/__init__.pyc'
I have set the `$PYTHONPATH` to `/usr/local/lib/python2.7/dist-packages`
And when looking at `sys.path` I get this output:
['', '/usr/local/lib/python2.7/dist-packages',... and 12 other locations]
It seems to have my desired location in first. Nevertheless the wrong module
gets loaded.
**EDIT:**
Contents of `$PATH`:
/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/release/bin:/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/debug/bin:/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/bin:/home/maid/phd/3rdpartySoft/art-2009-03-12/bin:/home/maid/phd/3rdpartySoft/ANTs-1.9.x-Linux/bin:/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/release/bin:/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/debug/bin:/misc/software-lin/lmbsoft/build/x86_64-gcc4.8/bin:/home/maid/phd/3rdpartySoft/art-2009-03-12/bin:/home/maid/phd/3rdpartySoft/ANTs-1.9.x-Linux/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:.:/home/maid/bin:/misc/software-lin/matlabR2015a/bin:/home/maid/phd/3rdpartySoft/nifty_reg-1.3/niftyreg_install/bin:/misc/software-lin/lmbsoft/cudatoolkit-3.2.16-x86_64/cuda/bin:/misc/database/cv2/local/bin:/misc/software-lin/vibez/bin:/usr/lib/jvm/java-6-openjdk/jre/bin:/misc/software-lin/vivi:/home/maid/localsoft/voreen/voreen-src-3.0.1-unix/bin/:/home/maid/tmp/ij146/ImageJ:.:/home/maid/bin:/misc/software-lin/matlabR2015a/bin:/home/maid/phd/3rdpartySoft/nifty_reg-1.3/niftyreg_install/bin:/misc/software-lin/lmbsoft/cudatoolkit-3.2.16-x86_64/cuda/bin:/misc/database/cv2/local/bin:/misc/software-lin/vibez/bin:/usr/lib/jvm/java-6-openjdk/jre/bin:/misc/software-lin/vivi:/home/maid/localsoft/voreen/voreen-src-3.0.1-unix/bin/:/home/maid/tmp/ij146/ImageJ
Any help appreciated, thanks, Dominic
Answer: I posit that if you `echo $PATH` you will find that `/usr/lib` is being
searched before `/usr/local/lib`. Because it finds it in `/usr/lib` first, it
will not go on to look in `/usr/local/lib`.
`sys.path` only covers the `$PYTHONPATH` variable and doesn't show you the
contents of `$PATH`.
|
Install h5py without sudo
Question: I'm trying to install `h5py` package via `pip` for python 2.7, I can't use
`sudo` and I have python 3.2 installed too.
Here is my attemp:
I have installed pip:
curl -O https://bootstrap.pypa.io/get-pip.py
python2.7 get-pip.py --user
then I installed `wheel`
`~/.local/bin/pip2.7 install --user wheel`
Collecting wheel
/home/myuser/.local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:315: SNIMissingWarning: An HTTPS request has been made, but the SNI (Subject Name Indication) extension to TLS is not available on this platform. This may cause the server to present an incorrect TLS certificate, which can cause validation failures. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#snimissingwarning.
SNIMissingWarning
/home/myuser/.local/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:120: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
Using cached wheel-0.29.0-py2.py3-none-any.whl
Installing collected packages: wheel
Successfully installed wheel-0.29.0
Then installed `h5py`, seems it failed.
`~/.local/bin/pip2.7 install --user h5py`
Collecting h5py
Using cached h5py-2.5.0.tar.gz
/usr/lib/python2.7/dist-packages/setuptools/command/install_scripts.py:3: UserWarning: Module pip was already imported from /home/myuser/.local/lib/python2.7/site-packages/pip/__init__.pyc, but /usr/lib/python2.7/dist-packages is being added to sys.path
from pkg_resources import Distribution, PathMetadata, ensure_directory
Requirement already satisfied (use --upgrade to upgrade): numpy>=1.6.1 in /usr/lib/python2.7/dist-packages (from h5py)
Requirement already satisfied (use --upgrade to upgrade): Cython>=0.17 in /home/myuser/.local/lib/python2.7/site-packages (from h5py)
Requirement already satisfied (use --upgrade to upgrade): six in /home/myuser/.local/lib/python2.7/site-packages (from h5py)
Building wheels for collected packages: h5py
Running setup.py bdist_wheel for h5py ... error
Complete output from command /usr/bin/python2.7 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-7KTR1Y/h5py/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" bdist_wheel -d /tmp/tmpE1KVSupip-wheel- --python-tag cp27:
usage: -c [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
or: -c --help [cmd1 cmd2 ...]
or: -c --help-commands
or: -c cmd --help
error: invalid command 'bdist_wheel'
----------------------------------------
Failed building wheel for h5py
Running setup.py clean for h5py
Failed to build h5py
Installing collected packages: h5py
Running setup.py install for h5py ... done
Successfully installed h5py-2.5.0
run python via `python2.7`
Python 2.7.3 (default, Feb 27 2014, 19:58:35)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import h5py
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/myuser/.local/lib/python2.7/site-packages/h5py/__init__.py", line 23, in <module>
from . import _conv
File "h5py/h5r.pxd", line 21, in init h5py._conv (/tmp/pip-build-7KTR1Y/h5py/h5py/_conv.c:7356)
File "h5py/_objects.pxd", line 12, in init h5py.h5r (/tmp/pip-build-7KTR1Y/h5py/h5py/h5r.c:2941)
File "h5py/_objects.pyx", line 1, in init h5py._objects (/tmp/pip-build-7KTR1Y/h5py/h5py/_objects.c:7226)
ImportError: /home/myuser/.local/lib/python2.7/site-packages/h5py/defs.so: undefined symbol: H5Oexists_by_name
What I'm doing wrong?
**Update:**
`~/.local/bin/pip2.7 show h5py`
---
Metadata-Version: 1.1
Name: h5py
Version: 2.5.0
Summary: Read and write HDF5 files from Python
Home-page: http://www.h5py.org
Author: Andrew Collette
Author-email: andrew dot collette at gmail dot com
License: UNKNOWN
Location: /home/myuser/.local/lib/python2.7/site-packages
Requires: numpy, Cython, six
My OS is Ubuntu 12.04.1 LTS.
Answer: So there's a few things happening here:
1. Missing SSL certificate problems (see the `urllib3` link)
2. `setuptools` not finding `wheel`, meaning a wheel isn't built, so `pip` calls `python setup.py install` directly
3. `h5py` is trying to use a function in HDF5 which does not exist in the version of HDF5 that's on your system.
1 and 2 are worth fixing (as they may be symptoms of other problems with the
system), but 3 is the reason `h5py` isn't working for you.
`h5py` is trying to access `H5Oexists_by_name`. According to
<https://www.hdfgroup.org/HDF5/doc/RM/RM_H5O.html#Object-ExistsByName>, this
first appeared in version 1.8.5 of HDF5. According to
<http://packages.ubuntu.com/source/precise/hdf5>, the version of HDF5 on your
system is 1.8.4 (but you need to check this!). Somehow `h5py` thinks the HDF5
library on you system is 1.8.5 or higher (see
<https://github.com/h5py/h5py/blob/4ee8f89b6dc658fdea5dc62d0f29058121928cfe/h5py/h5o.pyx#L172>)
It looks like someone else has run into a similar problem, and filed
<https://bugs.launchpad.net/ubuntu/+source/hdf5/+bug/1418220>. You probably
want to inform them of your problem, so that they can produce a bug fix.
|
Split Strings to change them
Question: I'm new with python,I'm trying to learn I hope you can help me. What I'm
trying to to is to change week day, something like this.
Today is {Mon|Tue|Wed|Thu|Fri} the best day.
**It suppose to change randonly those week days**. Do you have any idea? Thank
you!
Answer: This should work:
import random
days = ["Mon", "Tue", "Wed", "Thur", "Fri"]
random_choice = random.choice(days)
print("Today is " + random_choice + " the best day.")
|
'utf-8' decode error in tensorflow tutorial
Question: I'm running into this bizarre problem where when I run
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets('/home/fqiao/development/MNIST_data/', one_hot=True)
I get:
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.5/dist-packages/tensorflow/examples/tutorials/mnist/input_data.py", line 199, in read_data_sets
train_images = extract_images(local_file)
File "/usr/local/lib/python3.5/dist-packages/tensorflow/examples/tutorials/mnist/input_data.py", line 58, in extract_images
magic = _read32(bytestream)
File "/usr/local/lib/python3.5/dist-packages/tensorflow/examples/tutorials/mnist/input_data.py", line 51, in _read32
return numpy.frombuffer(bytestream.read(4), dtype=dt)[0]
File "/usr/lib/python3.5/gzip.py", line 274, in read
return self._buffer.read(size)
File "/usr/lib/python3.5/_compression.py", line 68, in readinto
data = self.read(len(byte_view))
File "/usr/lib/python3.5/gzip.py", line 461, in read
if not self._read_gzip_header():
File "/usr/lib/python3.5/gzip.py", line 404, in _read_gzip_header
magic = self._fp.read(2)
File "/usr/lib/python3.5/gzip.py", line 91, in read
self.file.read(size-self._length+read)
File "/usr/local/lib/python3.5/dist-packages/tensorflow/python/platform/default/_gfile.py", line 45, in sync
return fn(self, *args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/tensorflow/python/platform/default/_gfile.py", line 199, in read
return self._fp.read(n)
File "/usr/lib/python3.5/codecs.py", line 321, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte
However, if I just run the code in input_data.py directly, everything appears
to be fine:
>>> dt = numpy.dtype(numpy.uint32).newbyteorder('>')
>>> f = tf.gfile.Open('/home/fqiao/development/MNIST_data/train-images-idx3-ubyte.gz', 'rb')
>>> bytestream = gzip.GzipFile(fileobj=f)
>>> testbytes = numpy.frombuffer(bytestream.read(4), dtype=dt)[0]
>>> testbytes
2051
Anyone has any idea what's going on?
My system: Ubuntu 15.10 x64 python 3.5.0.
Answer: The bug has been addressed by a recent change
[555e73d](https://github.com/tensorflow/tensorflow/commit/555e73da8f171992085c68614f74b23b8180292c).
MNIST files need to be opened with binary 'rb' mode instead of just text 'r'.
|
Python Sqlite3 Database Locked, QWidget
Question: I'm getting a `sqlite3.OperationalError: database is locked` when I try to
update the database from a pyqt widget.
The main window shows a list of items in a database. When an item is double
clicked a widget will pop up with options to modify a value in the same row of
the database.
I have 4 separate .py files; (I have removed most of the code)
`DBmanager.py` that contains all the functions for interacting with the
database.
class DatabaseUtility:
def __init__(self, databaseFile):
self.db = databaseFile
self.conn = sqlite3.connect(self.db)
self.c = self.conn.cursor()
def ChangeItemQuantity(self, itemName, incramentQuantity):
try:
# Change given item quantity in database
self.c.execute('''
SELECT quantity
FROM items
WHERE itemName=?
''',(itemName,))
print(itemName)
print(incramentQuantity)
current_quantity = self.c.fetchone()
print(current_quantity[0])
new_quantity = current_quantity[0] + incramentQuantity
self.c.execute('''
UPDATE items
SET quantity = ?
WHERE itemName=?
''',(new_quantity, itemName))
self.conn.commit()
except Exception as error:
# Rollback any changes if something goes wrong.
self.conn.rollback()
raise error
def __del__(self):
"""Commit and close database connection when the class is terminated."""
# pass
self.conn.commit()
self.c.close()
self.conn.close()
`StartGui.py` that contains the functions for the GUI.
import sys
from PyQt4 import QtCore, QtGui
from guiFormat import Ui_MainWindow
from itemWidget import Ui_itemWidget
from DBmanager import DatabaseUtility
class MainWindow(QtGui.QMainWindow):
def __init__(self, parent=None):
QtGui.QWidget.__init__(self, parent)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.db = 'testdb.db'
self.dbUtil = DatabaseUtility(self.db)
self.ui.updateButton.clicked.connect(self.populateTable_default)
self.ui.updateButton.clicked.connect(self.dbUtil.UpdateDatabase)
self.ui.searchButton.clicked.connect(self.populateTable_search)
self.ui.tableWidget.doubleClicked.connect(self.open_item_widget)
self.ui.tableWidget.resizeRowsToContents()
# Populate table on initial startup
self.populateTable_default()
def open_item_widget(self):
self.item_widget = ItemWidget(self)
# self.item_widget.show()
column_count = self.ui.tableWidget.columnCount()
self.item_widget.ui.tableWidget.setColumnCount(column_count)
self.item_widget.ui.tableWidget.setRowCount(1)
column_names = self.dbUtil.GetColumns('items')
self.item_widget.ui.tableWidget.setHorizontalHeaderLabels(column_names)
row = self.ui.tableWidget.currentRow()
for column in range(column_count):
x = self.ui.tableWidget.item(row, column).text()
item_data = QtGui.QTableWidgetItem(str(x))
self.item_widget.ui.tableWidget.setItem(0, column, item_data)
self.item_widget.show()
class ItemWidget(QtGui.QWidget):
def __init__(self, parent=None):
self.db = 'testdb.db'
self.dbUtil2 = DatabaseUtility(self.db)
QtGui.QWidget.__init__(self, parent)
self.ui = Ui_itemWidget()
self.ui.setupUi(self)
self.ui.cancelOkButtonBox.rejected.connect(self.close)
self.ui.cancelOkButtonBox.accepted.connect(self.submit_changes)
def submit_changes(self):
# Get item Name.
item_name = self.ui.tableWidget.item(0,0).text()
# Get number from increment box.
quant_increment = self.ui.QuantSpinBox.value()
alert_incrament = self.ui.alertSpinBox.value()
print('Changing quantity...', item_name, quant_increment)
self.dbUtil2.ChangeItemQuantity(item_name, quant_increment)
self.close()
##======================================================================================================================
##======================================================================================================================
if __name__ == "__main__":
dbUtil = DatabaseUtility('testdb.db')
app = QtGui.QApplication(sys.argv)
mainwindow = MainWindow()
mainwindow.show()
# itemwidget = ItemWidget()
# itemwidget.show()
sys.exit(app.exec_())
`Mainwindow.py` is an export from pyqt designer for the main window.
`Itemwidget.py` is also an export from pyqt designer for the item widget.
Thank you for all your help.
Answer: The `sqlite3` documentation says:
> When a database is accessed by multiple connections, and one of the
> processes modifies the database, the SQLite database is locked until that
> transaction is committed.
Since you have two connections, one opened by `MainWindow` and the other by
`ItemWidget`, one likely cause of your problem is just what the doc says. One
connection tries to update the database when changes made by the other
connection is not committed. This won't happen with the `ChangeItemQuantity`
method you are showing as the change it makes is immediately committed, but
obviously `DatabaseUtility` has other methods you are not showing, like
`UpdateDatabase`. If they make changes that are not immediately committed,
that could be the problem.
Let `MainWindow` and `ItemWidget` share one connection and see if the problem
goes away. You can do this by making `conn` a shared attribute of
`DatabaseUtility` instances, with no change to callers:
class DatabaseUtility:
conn = None
def __init__(self, databaseFile):
self.db = databaseFile
if self.__class__.conn is None:
self.__class__.conn = sqlite3.connect(self.db)
self.c = self.conn.cursor()
Also, although this seems less likely to be the problem, if some other process
has an open transaction on the same SQLite database, the database will be
locked for as long as that transaction is active. Some apps have the bad habit
of maintaining an active transaction it seems. Whenever I open a database with
[SQLite Browser](http://sqlitebrowser.org/), I can't do anything to the
database from other programs (maybe I can turn that off, but I never bothered
to figure out how...)
|
Matplotlib not installing inside virtualenv mac
Question: So I have Python 3 and `matplotlib` installed globally. If I run python
outside of a virtual environment and import matplotlib to check the version it
shows 1.5.1 . But I am facing problems installing matplotlib within a virtual
environment. I created a virtual environment using the command `python3 -m
venv ds` and activated `ds`. These are the contents of my `requirements.txt`
`matplotlib==1.4.2 numpy==1.9.1`
When I do `pip3 install -r requirements.txt` I get this
Collecting matplotlib==1.4.2 (from -r requirements.txt (line 1))
Using cached matplotlib-1.4.2.tar.gz
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 20, in <module>
File "/private/var/folders/ym/gfrm424x31j4vd944cdhn4hr0000gn/T/pip-build-pcfq8bhb/matplotlib/setup.py", line 155, in <module>
result = package.check()
File "/private/var/folders/ym/gfrm424x31j4vd944cdhn4hr0000gn/T/pip-build-pcfq8bhb/matplotlib/setupext.py", line 962, in check
min_version='2.3', version=version)
File "/private/var/folders/ym/gfrm424x31j4vd944cdhn4hr0000gn/T/pip-build-pcfq8bhb/matplotlib/setupext.py", line 446, in _check_for_pkg_config
if (not is_min_version(version, min_version)):
File "/private/var/folders/ym/gfrm424x31j4vd944cdhn4hr0000gn/T/pip-build-pcfq8bhb/matplotlib/setupext.py", line 174, in is_min_version
return found_version >= expected_version
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/distutils/version.py", line 70, in __ge__
c = self._cmp(other)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/distutils/version.py", line 337, in _cmp
if self.version < other.version:
TypeError: unorderable types: str() < int()
IMPORTANT WARNING:
pkg-config is not installed.
matplotlib may not be able to find some of its dependencies
============================================================================
Edit setup.cfg to change the build options
BUILDING MATPLOTLIB
matplotlib: yes [1.4.2]
python: yes [3.5.1 (v3.5.1:37a07cee5969, Dec 5 2015,
21:12:44) [GCC 4.2.1 (Apple Inc. build 5666) (dot
3)]]
platform: yes [darwin]
REQUIRED DEPENDENCIES AND EXTENSIONS
numpy: yes [version 1.10.4]
six: yes [using six version 1.10.0]
dateutil: yes [dateutil was not found. It is required for date
axis support. pip/easy_install may attempt to
install it after matplotlib.]
pytz: yes [pytz was not found. pip will attempt to install
it after matplotlib.]
tornado: yes [tornado was not found. It is required for the
WebAgg backend. pip/easy_install may attempt to
install it after matplotlib.]
pyparsing: yes [pyparsing was not found. It is required for
mathtext support. pip/easy_install may attempt to
install it after matplotlib.]
pycxx: yes [Official versions of PyCXX are not compatible
with matplotlib on Python 3.x, since they lack
support for the buffer object. Using local copy]
libagg: yes [pkg-config information for 'libagg' could not
be found. Using local copy.]
----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/ym/gfrm424x31j4vd944cdhn4hr0000gn/T/pip-build-pcfq8bhb/matplotlib
You are using pip version 7.1.2, however version 8.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
How should I install matplotlib version 1.4.2 in virtual environment ?
My question has been marked as duplicate but that link doesn't solve my
question. The solution given is for Ubuntu
Answer: You can use the system package in your virtualenv with
[this](http://virtualenv.readthedocs.org/en/latest/userguide.html#the-system-
site-packages-option) option.
Otherwise, [this SO
post](http://stackoverflow.com/questions/27024731/matplotlib-compilation-
error-typeerror-unorderable-types-str-int) may help you.
|
Trying to python takes a variable in to Create Table
Question: I'm trying to python takes a variable when it ask for the data base name but
it does not work this is my code, I do not know whan I'm doing wrong.
any idea ?
#!/usr/bin/python
# -*- encoding: utf-8 -*-
import MySQLdb
name_db = raw_input('Type Data Base Name : ')
bd = MySQLdb.connect("localhost","root","9090i","clientes" )
cursor = bd.cursor()
sql = "CREATE TABLE name_db (NOMBRE CHAR(20) NOT NULL, APELLIDO CHAR(20), EDAD INT, SEXO CHAR(1), SALARIO FLOAT )"
cursor.execute(sql)
bd.close()
Answer: Change
sql = "CREATE TABLE name_db (NOMBRE CHAR(20) NOT NULL, APELLIDO CHAR(20), EDAD INT, SEXO CHAR(1), SALARIO FLOAT )"
to
sql = "CREATE TABLE {name} (NOMBRE CHAR(20) NOT NULL, APELLIDO CHAR(20), EDAD INT, SEXO CHAR(1), SALARIO FLOAT )".format(name = name_db)
The {name} is Python's syntax for string replacement so this should create a
constant SQL String that has the value you typed in substituted for the table
name.
To check this it's a good idea to print out the SQL before you execute it.
That makes it easier for you to see why the code isn't working.
|
Swift get user input with prompt
Question: In Swift, I want to have a continous user-input loop, much like how the python
interpreter works, where a prompt is made, you type a line, the result of the
line is displayed, and then the user is prompted again. This is my code so
far:
import Foundation
func input() -> String {
var keyboard = NSFileHandle.fileHandleWithStandardInput()
var inputData = keyboard.availableData
return NSString(data: inputData, encoding: NSUTF8StringEncoding) as! String
}
while true {
println("Obl>")
var theInput = input()
println("\(theInput)")
}
However, this results in a scheme like this:
Obl>
hello world
hello world
Obl>
yo
yo
What I want it to look like is this:
Obl> hello world
hello world
Obl> hello
hello
How can this be accomplished?
Answer: Are you still using Swift 1? `println` has been deprecated in Swift 2.
Swift 1:
print("Obl> ")
Swift 2:
print("Obl>", terminator: " ")
And instead of your `input()` function, you can just use `readLine`, which is
a standard function in Swift:
let theInput = readLine()
|
python logging performance comparison and options
Question: I am researching high performance logging in Python and so far have been
disappointed by the performance of the python standard logging module - but
there seem to be no alternatives. Below is a piece of code to performance test
4 different ways of logging:
import logging
import timeit
import time
import datetime
from logutils.queue import QueueListener, QueueHandler
import Queue
import threading
tmpq = Queue.Queue()
def std_manual_threading():
start = datetime.datetime.now()
logger = logging.getLogger()
hdlr = logging.FileHandler('std_manual.out', 'w')
logger.addHandler(hdlr)
logger.setLevel(logging.DEBUG)
def logger_thread(f):
while True:
item = tmpq.get(0.1)
if item == None:
break
logging.info(item)
f = open('manual.out', 'w')
lt = threading.Thread(target=logger_thread, args=(f,))
lt.start()
for i in range(100000):
tmpq.put("msg:%d" % i)
tmpq.put(None)
lt.join()
print datetime.datetime.now() - start
def nonstd_manual_threading():
start = datetime.datetime.now()
def logger_thread(f):
while True:
item = tmpq.get(0.1)
if item == None:
break
f.write(item+"\n")
f = open('manual.out', 'w')
lt = threading.Thread(target=logger_thread, args=(f,))
lt.start()
for i in range(100000):
tmpq.put("msg:%d" % i)
tmpq.put(None)
lt.join()
print datetime.datetime.now() - start
def std_logging_queue_handler():
start = datetime.datetime.now()
q = Queue.Queue(-1)
logger = logging.getLogger()
hdlr = logging.FileHandler('qtest.out', 'w')
ql = QueueListener(q, hdlr)
# Create log and set handler to queue handle
root = logging.getLogger()
root.setLevel(logging.DEBUG) # Log level = DEBUG
qh = QueueHandler(q)
root.addHandler(qh)
ql.start()
for i in range(100000):
logging.info("msg:%d" % i)
ql.stop()
print datetime.datetime.now() - start
def std_logging_single_thread():
start = datetime.datetime.now()
logger = logging.getLogger()
hdlr = logging.FileHandler('test.out', 'w')
logger.addHandler(hdlr)
logger.setLevel(logging.DEBUG)
for i in range(100000):
logging.info("msg:%d" % i)
print datetime.datetime.now() - start
if __name__ == "__main__":
"""
Conclusion: std logging about 3 times slower so for 100K lines simple file write is ~1 sec while std
logging ~3. If threads are introduced some overhead causes to go to ~4 and if QueueListener and events
are used with enhancement for thread sleeping that goes to ~5 (probably because log records are being
inserted into queue).
"""
print "Testing"
#std_logging_single_thread() # 3.4
std_logging_queue_handler() # 7, 6, 7 (5 seconds with sleep optimization)
#nonstd_manual_threading() # 1.08
#std_manual_threading() # 4.3
1. The nonstd_manual_threading option works best since there is no overhead of the logging module but obviously you miss out on a lot of features such as formatters, filters and the nice interface
2. The std_logging in a single thread is the next best thing but still about 3 times slower than nonstd manual threading.
3. The std_manual_threading option dumps messages into a threadsafe queue and in a separate thread uses the standard logging module. That comes out to be about 25% higher than option 2, probably due to context switching costs.
4. Finally, the option using "logutils"'s QueueHandler comes out to be the most expensive. I tweaked the code of logutils/queue.py's _monitor method to sleep for 10 millis after processing 500 messages as long as there are less than 100K messages in the queue. That brings the runtime down from 7 seconds to 5 seconds (probably due to avoiding context switching costs).
My question is, why is there so much performance overhead with the logging
module and are there any alternatives? Being a performance sensitive app does
it even make sense to use the logging module?
p.s.: I have profiled the different scenarios and seems like LogRecord
creation is expensive.
Answer: If you want a better answer try to describe your problem in more detail, why
you need such a huge number of messages to log? Logging was designed to record
important information, especially warnings and errors, not every line you
execute.
If logging takes more than 1% of your processing time, probably you are using
it wrongly and that's not logging fault.
Second, related to performance: do not build the message before sending it to
logging module (replace format % params with format command params). This is
because logging does this for you, but much faster.
|
Why subprocess.call () is showing error in linux?
Question: Let us consider Linux platform where I need to execute a program called
smart.exe which uses input.dat file. Both the files are placed in the same
directory with each file having the same file permission 777.
Now if I run the following command in the terminal window smart.exe is fully
executed without any error.
$./smart.exe input.dat
On the other hand, if I use the following python script called my_script.py
placed in the same directory, then I get an error.
my_script.py has the following code:
#!/usr/bin/python
import os, subprocess
exit_code = subprocess.call("./smart.exe input.dat", shell = False)
The error is as follows:
File "my_script.py", line 4, in <module>
exit_code = subprocess.call("./smart.exe input.dat", shell = False)
File "/usr/lib64/python2.6/subprocess.py", line 478, in call
p = Popen(*popenargs, **kwargs)
File "/usr/lib64/python2.6/subprocess.py", line 642, in __init__
errread, errwrite)
File "/usr/lib64/python2.6/subprocess.py", line 1234, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
Can someone please tell me why this is happening. Please note that the
smart.exe should take around 10 sec to fully complete. This may be a clue for
the problem.
Please also advise if there is any other way to run smart.exe from
my_script.py. Your solution is much appreciated!
Answer: You should decide if you want shell support or not.
If you want the shell to be used (which is not necessary here), you should use
`exit_code = subprocess.call("./smart.exe input.dat", shell=True)`. Then the
shell interprets your command line.
If you don't want it (as you don't need it and want to avoid unnecessary
complexity), you should do `exit_code = subprocess.call(["./smart.exe",
"input.dat"], shell=False)`.
(And there is no point naming your binarys `.exe` under Linux.)
|
Python: how to create a submatrix discretizing a circle?
Question: In a 2D square grid (matrix) full of `zeros`, I need to create a submatrix
full of `ones`, with the shape of this submatrix being as close as possible to
a circle. I know a circle cannot be precisely represented when you work with
cells or pixels, therefore I aim at a discretized circle.
The best thing I could come up with was this code, which produces **square
submatrices** (the blue square in the image below):
from __future__ import division
import numpy
import matplotlib.pyplot as plt
import matplotlib.colors as mc
import random
import os
import math
n=101 #Grid size
empty_lattice=numpy.zeros((n,n)) #The empty 2D grid
x=int(numpy.random.uniform(0,n-1)) #X coord. top left corner
y=int(numpy.random.uniform(0,n-1)) #Y coord. top left corner
side=int(numpy.random.uniform(15,n)) #Side of the square approximating the circle
max_y=n-y #Checks the distance between the y of the submatrix origin and the matrix vertical boundary
max_x=n-x #Checks the distance between the x of the submatrix origin and the matrix horizontal boundary
max_width=0 #Initializes a maximum width for the loading submatrix
if max_y<max_x: #This assigns the minimum value between max_y and max_x to max_width, so that the submatrix is always a square
max_width=max_y
else:
max_width=max_x
if side>max_width:
for i in range(0,max_width):
for j in range(0, max_width):
empty_lattice[x+i][y+j]=1
else:
for i in range(0, side):
for j in range(0, side):
empty_lattice[x+i][y+j]=1
Now, visually this translates into the following image, but as you know there
is a noticeable difference between the blue square and the inscribed circle in
terms of area: [](http://i.stack.imgur.com/kmeWz.png)
**My question:** how could I amend my code in order to be able to "smooth" the
corners of my squares so that something which resembles a circle appears?
**EDIT**
The circles should be drawn even if they do not entirely reside within the
grid boundaries (look at the image).
Answer: This function fills in a circle of 1s that looks pretty good.
def fill_cell(cell, corner, rad):
m, n = cell.shape
ctr = corner[0]+m/2, corner[1]+n/2
x = np.arange(m) - ctr[0]
y = np.arange(n) - ctr[1]
X,Y = np.meshgrid(x, y, order='ij') # could try order='xy'
Z = ((X**2 + Y**2)<= rad**2).astype(cell.dtype)
return Z
empty_lattice[:] = fill_cell(empty_lattice, (x,y),side/2)
Position in `empty_lattice` is not right - because of a difference in how you
are defining the `x,y` coordinates and my assumptions, but I think you can
sort that out.
Radius looks good, though it might be off by an integer.
To fill in multiple circles, you could iterate over the `x,y` values, and
assign lattice values for a slice (view)
xyslice = slice(x,15), slice(y,15)
empty_lattice[xyslice] = fill_cell(empty_lattice[xyslice],...)
For overlapping circles I'd look into some sort of logical assignment
empty_lattice[xyslice] |= fill_cell(...)
|
Python using classmethod for multiple constructors
Question: I have been struggling trying to create multiple constructors with the
classmethod decorator. There is an example in SO - [What is a clean, pythonic
way to have multiple constructors in
Python?](http://stackoverflow.com/questions/682504/what-is-a-clean-pythonic-
way-to-have-multiple-constructors-in-python) (second answer)
class Cheese(object):
def __init__(self, num_holes=0):
"defaults to a solid cheese"
self.number_of_holes = num_holes
@classmethod
def random(cls):
return cls(random(100))
@classmethod
def slightly_holey(cls):
return cls(random(33))
@classmethod
def very_holey(cls):
return cls(random(66, 100))
However this example is not very clear and the code does not work for me in
python 3 when typing the commands given:
gouda = Cheese()
emmentaler = Cheese.random()
leerdammer = Cheese.slightly_holey()
giving -
AttributeError: type object 'Cheese' has no attribute 'random'
as this is one of the only examples I can find.
Answer: `randint` should work:
from random import randint
class Cheese(object):
def __init__(self, num_holes=0):
"defaults to a solid cheese"
self.number_of_holes = num_holes
@classmethod
def random(cls):
return cls(randint(0, 100))
@classmethod
def slightly_holey(cls):
return cls(randint(0, 33))
@classmethod
def very_holey(cls):
return cls(randint(66, 100))
gouda = Cheese()
emmentaler = Cheese.random()
leerdammer = Cheese.slightly_holey()
Now:
>>> leerdammer.number_of_holes
11
>>> gouda.number_of_holes
0
>>> emmentaler.number_of_holes
95
|
Calling Popen in Python on a MAC - Error can not find file
Question: When I try to shell out of my Python 3.51 program to run the Popen command I
get the following errors. Yet when I copy the exact string I'm passing to
Popen to the Terminal command line it works fine and opens the file in Adobe
Reader which is my default app for the .pdf files.
Here is the Code:
>
> finalCall = r'open /Users/gbarnabic/Documents/1111/combined.pdf'
> print(finalCall)
> pid_id = subprocess.Popen(finalCall).pid
>
Here is the error:
> open /Users/gbarnabic/Documents/1111/combined.pdf Exception in Tkinter
> callback Traceback (most recent call last): File
> "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/tkinter/**init**.py",
> line 1549, in **call** return self.func(*args) File "pdfcomb2.py", line 212,
> in change_dir self.openPDF(outFileName, pageNum) File "pdfcomb2.py", line
> 426, in openPDF subprocess.run(finalCall) File
> "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py",
> line 696, in run with Popen(*popenargs, **kwargs) as process: File
> "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py",
> line 950, in **init** restore_signals, start_new_session) File
> "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py",
> line 1544, in _execute_child raise child_exception_type(errno_num, err_msg)
> FileNotFoundError: [Errno 2] No such file or directory: 'open
> /Users/gb/Documents/1111/combined.pdf' Georges-MBP:filepicktest gb$ open
> /Users/gb/Documents/1111/combined.pdf Georges-MBP:filepicktest gb$
Answer: With Popen you need to set `shell=True` to pass command as a string or split
command in a list of arguments. Could be done with `shlex`
import shlex
import subprocess
subprocess.Popen(shlex.split('open ....'))
You could check example in documentation:
<https://docs.python.org/2/library/subprocess.html#subprocess.Popen>
So the error here means that Python try to run file with name `open
/Users/gb/Documents/1111/combined.pdf`. Obviously it doesn't exist
|
Python 3.4 - Installing Kivy Error
Question: I'm trying to install Kivy on Python 3.4 using the instructions here:
<https://kivy.org/docs/installation/installation-windows.html>
I'm on the installing dependencies step, where it gives me this error:
<http://prntscr.com/a5rk5k>
Initially I tried just going ahead to the last step (python -m pip install
kivy) and it looked like it worked fine, but then I tried import kivy in a
Visual Studio project and it said "Unable to resolve "kivy""
Any ideas anyone? Keep in mind, I had Python 3.5 installed (which kivy does
not work with) before now and set to default, but I changed the path in the
command prompt.
Answer: Something is not right with your kivy installation, use `python -m pip list`
to check what packages are missing and (re)install them, one-by-one would be
the best for debugging. And also you've pasted it wrong, so the
`kivy.deps.gstreamer` was read as a separate comand and not a package for
`pip`
For simple installing of kivy just follow the install docs or if you don't
mind having another folder or reinstalling python for new kivy&python try
[KivyInstaller](https://github.com/KeyWeeUsr/KivyInstaller) which hopefully
makes the whole process beginnerproof. You enter what you need in the
beginning and then wait.
|
How to catch Python3 SocketIO error
Question: I'm making a simple app that uses
[socketIO_client](https://pypi.python.org/pypi/socketIO-client). I can't
figure out how to "catch" the error when the connection fails.
from socketIO_client import SocketIO, LoggingNamespace
sock = SocketIO("localhost", 3000, LoggingNamespace)
When the server is offline the following is printed in the console:
WARNING:root:localhost:3000/socket.io [waiting for connection] HTTPConnectionPool(host='localhost', port=3000): Max retries exceeded with url: /socket.io/?EIO=3&transport=polling&t=1455989769325-0 (Caused by <class 'ConnectionRefusedError'>: [Errno 111] Connection refused)
But an exception isn't raised that I can catch and I tried creating my own
namespace class with `on_error`, `on_disconnect`, and `on_event`functions
defined but none of them were executed. [This
answer](http://stackoverflow.com/questions/29714822/python3-catch-errors-when-
from-self-connectbadhost-6667) didn't work either.
How can I "catch" this error so I can handle it properly? Alternatively, where
can I find more detailed documentation? Thanks!
Answer: The `LoggingMixin` of `socketIO_client` very explicitly turns the exception
into a string and logs it; you'll have to subclass `SocketIO` and customise
the loop that implements retrying things for a number of seconds. If you
simply want to let the exception bubble up the first time it occurs
(independent of the time-out):
from socketIO_client import SocketIO, LoggingNamespace import
socketIO_client.logs
class MySocketIO(SocketIO):
def _yield_warning_screen(self, seconds=None):
yield from socketIO_client.logs._yield_elapsed_time(seconds)
sock = MySocketIO("localhost", 3000, LoggingNamespace)
For more complex behaviour like raising only after timing out, a more complex
loop implementation in place of the transparent `yield from` is needed.
|
Python3: Popen communication
Question: I'm a gamer, and a coder. In one of my game, minecraft, I need a server, so,
with a friend, I bought one. But, this friend doesn't understand anything of
coding and, in particular, of the Linux' bash, so he can't switch on/off our
server, and he can't work on it. So I decied to make a program that help him
with our server. The point is that the server is coded in java (it is a jar)
and I can't acces to it without external commands. So, I reed lots of docs,
and all of these docs said to me: Β«You must use subprocess!Β»!! So I used it,
but I have a BIG problem in this Popen object Note before the problem: my
program doesn't just switch on/off the server, it is a server with the
relatives clients that allow to interract with the minecraft server and it
uses some socket and threading libreries.
So, the problem is:
class getOutput(Thread):
def __init__(self,outProc,connection):
self.proc = outProc #My Popen object
self.connection = connection #a socket object (my server biding)
self.stop = False #A way to stop this thread is to put getOutput.stop = True
Thread.__init__(self)
def run(self):
proc = self.proc
conn = self.connection
while True:
if self.stop: #if getOutput.stop = True, stop the thread
break
out = proc.stdout.readlines() #My problem...
for lines in out:
print(out) #My output where the server is started
conn.send(line) #send to client the output of the server
def StartMcServ():
global proc, conn, outputManager, McServStarted #Because it's a server and I must launch the minecraft server more than once
print('[Server/Info] Started McServ!') #Info is always useful
logfile.log('[Server/Info] Started McServ!') #a librery that I created that log in a file, ignore this line
proc = sh.Popen(JavaServ(),stdin=PIPE,stdout=PIPE,stderr=PIPE) #sh=subprocess, I did a from subprocess import PIPE,STDOUT ; import subprocess as sh because of the functions of subprocess have the same name that my libreries
outputManager = getOutput(proc,conn) #My thread, that have the process and the connection
outputManager.start()
def PutInput(*,Input=None): #A function that put input in my server
if Input and type(Input) == type(b'') and Input.endswith(b'\n'):
proc.stdin.write(Input)
so, **I really don't know** what is the problem, but the communication with
the server doesn't work, I'm sooooo sad of it
_P.S.: I dont put all the program or the main of it because of its lengh :D
P.S. (2): I'm sorry if I did english mistakes, but I'm 13 and I'm learning it
at school_
Answer: Sorry if I didnt anwer before, I just had a LOT of work, but I found where my
problem comes. I want to have output of an Popen class in real time, so I do
some
while True:
a = proc.stdout.readlines() #proc is my Popen class, my problem...
for line in a:
srv.send(bytes(a)) #srv is a socket class that I configure, I prefer to dont add all of this shit here
if self.stop == True:
break
What I wanna do is that my readlines function blocks while proc gives an
output, but it just sucks up my CPU, and I cry
|
How to run external Python script in Golang?
Question: I would like to run an external Python script that gets 4 arguments. If I
would like to run the Python script in cmd it would look like this: python
Required\Python\screenshot.py-master\screenshot.py --nojs -thumb
<http://google.com/> Required\Images\Screenshots\google.jpg So, I would like
to run this command from Go. How could I implement this? Thanks.
Answer: If examples from doc are not helpful, maybe this will make it easier for you.
test.go:
package main
import (
"log"
"os"
"os/exec"
)
func main() {
log.Println(os.Args)
if len(os.Args) == 1 {
return
}
cmd := exec.Command(os.Args[1], os.Args[2:]...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
log.Println(cmd.Run())
}
test.py:
import sys
print sys.argv
usage:
$ go run test.go python test.py 1 two 3 four
2016/02/20 21:45:42 [/tmp/go-build772613382/command-line-arguments/_obj/exe/test python test.py 1 two 3 four]
['test.py', '1', 'two', '3', 'four']
2016/02/20 21:45:42 <nil>
|
Tuple looping (I think)
Question: I have this code for a quiz but only the first question appears. I can answer
the first question and the score will adjust accordingly however the next
question never appears. I have tried researching looping through tuples and
have played around with my code but to no avail. I am a Python newbie and
would appreciate some help please. I have spent hours on it believe me.
from tkinter import *
root = Tk()
root.title("End of year exam")
score = 0
def submit_button_clicked():
global score
global questions
score = 0
if answer.get() == questions[0][1]:
score+=1
else:
score = score
scoretxt.config(text = "Your score is: {}".format(str(score)))
questions =[("What does 13 + 5 = ?","18"),("What does 12 + 8 = ?","20"),("What does 19 + 6 = ?","25"),("What does 17 + 15 = ?","32")]
Label(root,text = "Question : ",bg ="light grey").grid(row = 0,column = 0, sticky = W)
question=Label(root,bg = "light green",text= questions[1][0], width = 38)
question.grid(row =1,column=0)
Label(root,text = "Answer: ",bg = "light grey").grid(row = 2, column = 0, sticky = W)
answer = Entry(root,bg ="white",width = 45, justify = CENTER)
answer.grid(row = 3,column=0)
scoretxt = Label(root,text ="Your score is:",bg = "light green", width = 38)
scoretxt.grid(row = 10,column = 0, sticky = W)
### make a submit button
Button(root,text= "Submit",bg = "light grey",command = submit_button_clicked).grid(row = 4,column = 0, sticky = W)
root.mainloop()
Answer: This should work. I added a `try` statement in the function
`submit_button_clicked()` so if the question was the last one it would still
update the score. If you read through the code you should see what I changed.
Let me no if you don't understand it. Have a great day!
from tkinter import *
root = Tk()
root.title("End of year exam")
score = 0
questions =[("What does 13 + 5 = ?","18"),("What does 12 + 8 = ?","20"),("What does 19 + 6 = ?","25"),("What does 17 + 15 = ?","32")]
current_question = 0
def submit_button_clicked():
global score
global questions
global current_question
if answer.get() == questions[current_question][1]:
score += 1
current_question += 1
try:
question.config(text=questions[current_question][0])
except:
pass
answer.delete(0, 'end')
scoretxt.config(text = "Your score is: {}".format(str(score)))
Label(root,text = "Question : ",bg ="light grey").grid(row = 0,column = 0, sticky = W)
question=Label(root,bg = "light green",text=questions[current_question][0], width = 38)
question.grid(row =1,column=0)
Label(root,text = "Answer: ",bg = "light grey").grid(row = 2, column = 0, sticky = W)
answer = Entry(root,bg ="white",width = 45, justify = CENTER)
answer.grid(row = 3,column=0)
scoretxt = Label(root,text ="Your score is:",bg = "light green", width = 38)
scoretxt.grid(row = 10,column = 0, sticky = W)
### make a submit button
Button(root,text= "Submit",bg = "light grey",command = submit_button_clicked).grid(row = 4,column = 0, sticky = W)
root.mainloop()
|
Make array from Requests.get in python
Question: I Do the following :
@app.route('/api/test/', methods=['GET'])
def catalogue1():
cache = []
r = requests.get("http://192.168.198.140:5000/api/listdir")
cache = r.content
cache = ["vagrant.txt", "Securite_sociale.jpg"] ;
when i try to print cache[0] i get "[" .
How can i transform this result to an array .
Answer: I know nothing about Flask but it looks like `r.content` is a string, yet to
be de-serialized into a Python list. e.g. rather than
cache = ["vagrant.txt", "Securite_sociale.jpg"]
you have:
cache = '["vagrant.txt", "Securite_sociale.jpg"]'
I'm presuming it's JSON, in which case you could fix this with
import json
cache = json.loads(r.content)
But I'm also presuming there's a built-in way to do this in Flask
|
How to convert a wav file -> bytes-like object?
Question: I'm trying to programmatically analyse wav files with the audioop module of
Python 3.5.1 to get channel, duration, sample rate, volumes etc. however I can
find no documentation to describe how to convert a wav file to the 'fragment'
parameter which must be a bytes-like object.
Can anybody help?
Answer: [file.read()](https://docs.python.org/3/library/functions.html#open) returns a
`bytes` object, so if you're just trying to get the contents of a file as
`bytes`, something like the following would suffice:
with open(filename, 'rb') as fd:
contents = fd.read()
However, since you're working with
[audioop](https://docs.python.org/3/library/audioop.html), what you need is
raw _audio data_ , not raw file contents. Although uncompressed WAVs contain
raw audio data, they also contain headers which tell you important parameters
about the raw audio. Also, these headers must not be treated as raw audio.
You probably want to use the
[wave](https://docs.python.org/3/library/wave.html) module to parse WAV files
and get to their raw audio data. A complete example that reverses the audio in
a WAV file looks like this:
import wave
import audioop
with wave.open('intput.wav') as fd:
params = fd.getparams()
frames = fd.readframes(1000000) # 1 million frames max
print(params)
frames = audioop.reverse(frames, params.sampwidth)
with wave.open('output.wav', 'wb') as fd:
fd.setparams(params)
fd.writeframes(frames)
|
python kivy i don't see just an empty window
Question: I made my first kivy program. When I run this app, then it appears empty
window.
This is the whole program.
Python code:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty, StringProperty
class Myfirstwidget(BoxLayout):
def text(self, val):
print('text input text is: {txt}'.format(txt=val))
class MainAPP(App):
def build(self):
return Myfirstwidget()
if __name__ == '__main__':
MainAPP().run()
Kivy code `myfirstwidget.kv` :
#:kivy 1.9.1
<Myfirstwidget>:
Button:
on_press: self.text(txt_inpt.text)
TextInput:
id: txt_inpt
Answer: Change name of the kv file to `main.kv`.
Its name must be like the name of the App class, but lower case, and without
'app'. More info here [docs](https://kivy.org/docs/guide/lang.html#how-to-
load-kv).
|
Django, python syntax error while running makemigrations (DecimalField choices)
Question: In my application, I'm calling API to create choices for DecimalField in
models.py.
# -*- coding: utf-8 -*-
from django.db import models
import re
from suds.client import Client
from datetime import datetime
from django.utils import timezone
class Allegro:
def __init__(self):
self.webapi_key = 'hidden key'
self.country = 1
self.client = Client('https://webapi.allegro.pl/service.php?wsdl')
self.client.options.cache.setduration(hours=1)
self.starting_time = '24h'
def get_categories(self):
category_list = self.client.service.doGetCatsData(
countryId=self.country,
webapiKey=self.webapi_key
).catsList.item
categories = []
for item in category_list:
categories.append({'id': item.catId, 'name': item.catName, 'parent': item.catParent})
return categories
# search for free only, with time fixed at 24h. User can set phrase and category only.
def search(self, category, phrase):
params = [{
'item': ({'filterId': 'category', 'filterValueId': {'item': category}},
{'filterId': 'startingTime', 'filterValueId': {'item': self.starting_time}},
{'filterId': 'search', 'filterValueId': {'item': phrase}})
}]
search_raw_result = self.client.service.doGetItemsList(
countryId=self.country,
webapiKey=self.webapi_key,
filterOptions=params,
).itemsList.item
search = []
for item in search_raw_result:
search.append({'id': item.itemId, 'name': item.itemTitle,
'type': item.priceInfo.item[0].priceType, 'price': item.priceInfo.item[0].priceValue})
return search
def choices():
choice_prep = Allegro()
choice = choice_prep.get_categories()
choice_list = []
add = "'"
for item in choice:
if item['parent'] == 0:
item_name = add + item['name'] + add
choice_list.append([item['id'], item_name])
return choice_list
class FreeSearch(models.Model):
a = choices()
mail = models.CharField(verbose_name='mail', max_length=100)
phrase = models.CharField(verbose_name='phrase', max_length=150)
category = models.DecimalField(verbose_name='category', max_digits=6, decimal_places=0, choices=a)
end_date = models.DateTimeField(verbose_name="Data koΕcowa", blank=True)
activation_key = models.CharField(max_length=40, blank=True)
key_expires = models.DateTimeField(default=timezone.now)
def __str__(self):
return '%s, %s, %s' % (self.mail, self.phrase, self.category)
class Meta:
verbose_name = "Wyszukanie"
verbose_name = "Wyszukania"
Choices should be list of lists where are only two values, id which is decimal
max 5 digits and name which contains category names in Allegro auction
service.
After calling python manage.py makemigrations in cmd following problem occurs:
C:\Users\Dom\allewatcher>python manage.py makemigrations
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "C:\Python35\lib\site-packages\django\core\management\__init__.py", line
351, in execute_from_command_line
utility.execute()
File "C:\Python35\lib\site-packages\django\core\management\__init__.py", line
343, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Python35\lib\site-packages\django\core\management\base.py", line 394,
in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Python35\lib\site-packages\django\core\management\base.py", line 445,
in execute
output = self.handle(*args, **options)
File "C:\Python35\lib\site-packages\django\core\management\commands\makemigrat
ions.py", line 63, in handle
loader = MigrationLoader(None, ignore_no_migrations=True)
File "C:\Python35\lib\site-packages\django\db\migrations\loader.py", line 47,
in __init__
self.build_graph()
File "C:\Python35\lib\site-packages\django\db\migrations\loader.py", line 176,
in build_graph
self.load_disk()
File "C:\Python35\lib\site-packages\django\db\migrations\loader.py", line 102,
in load_disk
migration_module = import_module("%s.%s" % (module_name, migration_name))
File "C:\Python35\lib\importlib\__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 986, in _gcd_import
File "<frozen importlib._bootstrap>", line 969, in _find_and_load
File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 658, in exec_module
File "<frozen importlib._bootstrap_external>", line 764, in get_code
File "<frozen importlib._bootstrap_external>", line 724, in source_to_code
File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
File "C:\Users\Dom\allewatcher\search\migrations\0001_initial.py", line 20
('category', models.DecimalField(decimal_places=0, max_digits=6, verbose_nam
e='category', choices=[[26013, Antyki i Sztuka], [98553, Bilety], [64477, Biuro
i Reklama], [19732, BiΕΌuteria i Zegarki], [73973, Delikatesy], [11763, Dla Dziec
i], [5, Dom i OgrΓ³d], [63757, Erotyka], [20585, Filmy], [8845, Fotografia], [9,
Gry], [122640, Instrumenty], [6, Kolekcje], [2, Komputery], [122233, Konsole i a
utomaty], [7, KsiΔ
ΕΌki i Komiksy], [3, Motoryzacja], [1, Muzyka], [20782, Nieruch
omoΕci], [1454, OdzieΕΌ, Obuwie, Dodatki], [16696, PrzemysΕ], [76593, RΔkodzieΕo]
, [10, RTV i AGD], [3919, Sport i Turystyka], [122332, SprzΔt estradowy, studyjn
y i DJ-ski], [4, Telefony i Akcesoria], [1429, Uroda], [55067, Wakacje], [121882
, Zdrowie]])),
^
SyntaxError: invalid syntax
I also don't know why in error description there's no quotation marks added by
add variable in choices function.
# -*- coding: utf-8 -*-
from **future** import unicode_literals
from django.db import migrations, models import django.utils.timezone
class Migration(migrations.Migration):
dependencies = [
]
operations = [
migrations.CreateModel(
name='FreeSearch',
fields=[
('id', models.AutoField(auto_created=True, verbose_name='ID', primary_key=True, serialize=False)),
('mail', models.CharField(max_length=100, verbose_name='mail')),
('phrase', models.CharField(max_length=150, verbose_name='phrase')),
('category', models.DecimalField(decimal_places=0, max_digits=6, verbose_name='category', choices=[[26013, Antyki i Sztuka], [98553, Bilety], [64477, Biuro i Reklama], [19732, BiΕΌuteria i Zegarki], [73973, Delikatesy], [11763, Dla Dzieci], [5, Dom i OgrΓ³d], [63757, Erotyka], [20585, Filmy], [8845, Fotografia], [9, Gry], [122640, Instrumenty], [6, Kolekcje], [2, Komputery], [122233, Konsole i automaty], [7, KsiΔ
ΕΌki i Komiksy], [3, Motoryzacja], [1, Muzyka], [20782, NieruchomoΕci], [1454, OdzieΕΌ, Obuwie, Dodatki], [16696, PrzemysΕ], [76593, RΔkodzieΕo], [10, RTV i AGD], [3919, Sport i Turystyka], [122332, SprzΔt estradowy, studyjny i DJ-ski], [4, Telefony i Akcesoria], [1429, Uroda], [55067, Wakacje], [121882, Zdrowie]])),
('end_date', models.DateTimeField(blank=True, verbose_name='Data koΕcowa')),
('activation_key', models.CharField(max_length=40, blank=True)),
('key_expires', models.DateTimeField(default=django.utils.timezone.now)),
],
options={
'verbose_name': 'Wyszukania',
},
),
]
Answer: The problems seems to be in this item:
OdzieΕΌ, Obuwie, Dodatki
You have a '**,** ' sign there which causes syntax error - this value is put
directly into `0001_initial.py` file and then makes impression that list item
has 4 items instead of two.
To fix it just remove comma from it's value or just escape it somehow (for
example by using HTML entity `,` \- but it depends on how you are using it
further)
* * *
**EDIT**
Although commas cause problem directly it seems that issue lays deeper. You
migration's code's strings were generated without aphostrophes what causes the
problem.
I have checked your code - I have created app, copied your code and run
python manage.py makemigrations stack
_stack is name of my application BTW_
String have been generated with aphostrophes
('category', models.DecimalField(choices=[[26013, "'Antyki i Sztuka'"], [98553, "'Bilety'"], [64477, "'Biuro i Reklama'"], [19732, "'Bi\u017cuteria i Zegarki'"], [73973, "'Delikatesy'"], [11763, "'Dla Dzieci'"], [5, "'Dom i Ogr\xf3d'"], [63757, "'Erotyka'"], [20585, "'Filmy'"], [8845, "'Fotografia'"], [9, "'Gry'"], [122640, "'Instrumenty'"], [6, "'Kolekcje'"], [2, "'Komputery'"], [122233, "'Konsole i automaty'"], [7, "'Ksi\u0105\u017cki i Komiksy'"], [3, "'Motoryzacja'"], [1, "'Muzyka'"], [20782, "'Nieruchomo\u015bci'"], [1454, "'Odzie\u017c, Obuwie, Dodatki'"], [16696, "'Przemys\u0142'"], [76593, "'R\u0119kodzie\u0142o'"], [10, "'RTV i AGD'"], [3919, "'Sport i Turystyka'"], [122332, "'Sprz\u0119t estradowy, studyjny i DJ-ski'"], [4, "'Telefony i Akcesoria'"], [1429, "'Uroda'"], [55067, "'Wakacje'"], [121882, "'Zdrowie'"]], decimal_places=0, max_digits=6, verbose_name=b'category')),
If it is possible I recommend you to delete all files in
**your_application/migrations** (avoiding delete `__init__.py`!) and then try
to recreate migration by using standard `makemigrations` command.
I have been using Django in 1.9.2 version, suds 0.4 and Python 2.7
|
Django M2MFields 'through' widgets
Question: Are there exists any examples of Django widgets which can be useful for
ManyToManyFields with 'through' attributes? For example, i have these models
(got the source from django documentation):
from django.db import models
class Person(models.Model):
name = models.CharField(max_length=128)
def __str__(self): # __unicode__ on Python 2
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership')
def __str__(self): # __unicode__ on Python 2
return self.name
class Membership(models.Model):
person = models.ForeignKey(Person, on_delete=models.CASCADE)
group = models.ForeignKey(Group, on_delete=models.CASCADE)
date_joined = models.DateField()
invite_reason = models.CharField(max_length=64)
Obvisously, standart ModelMultipleChoiceField won't work here. I need to
populate 'date_joined' , and 'invite_reason' while adding. Which is the
simpliest way to achieve this?
Answer: This is a bit too complex for a simple widget. I can't even imagine how it
would look like. You will have to use [inline
formsets](https://docs.djangoproject.com/en/1.9/topics/forms/modelforms/#inline-
formsets) for that purpose.
This should give something like this:
from django.forms import inlineformset_factory
MembershipFormSet = inlineformset_factory(Group, Membership, fields=(
'person', 'date_joined', 'invite_reason'))
group = Group.objects.get(pk=group_id)
formset = MembershipFormSet(instance=group)
Within `django.contrib.admin`, you can use inlines with
[InlineModelAdmin](https://docs.djangoproject.com/en/1.9/ref/contrib/admin/#django.contrib.admin.InlineModelAdmin).
|
ImportError: Could not import the Python Imaging Library (PIL) required to load image files
Question: I am trying to run the average.py program in the facemorpher 1.0.1 python
package. I have created a virtual environment that has openCV installed with
homebrew, python 2.7 installed in homebrew, and executable `frameworkpython`
that makes a framework build of python inside the virtual environment `cv`.
running the average program currently gives me this output.
(cv) Francess-MacBook-Pro-2:face_morpher Megan$ frameworkpython facemorpher/averager.py --images=IMFDB_final/Ali/HelloBrother/images --out=average.png
Traceback (most recent call last):
File "facemorpher/averager.py", line 94, in <module>
args['--out'], args['--plot'])
File "facemorpher/averager.py", line 61, in averager
img, points = load_image_points(path, size)
File "facemorpher/averager.py", line 46, in load_image_points
img = scipy.ndimage.imread(path)[..., :3]
File "/Users/Megan/.virtualenvs/cv/lib/python2.7/site-packages/scipy/ndimage/io.py", line 25, in imread
raise ImportError("Could not import the Python Imaging Library (PIL)"
ImportError: Could not import the Python Imaging Library (PIL) required to load image files. Please refer to http://pypi.python.org/pypi/PIL/ for installation instructions.
Can I install Pillow to fix this error, and where should i install my PIL or
Pillow path to fix this?
Answer: resolved by doing `pip install Pillow` in the virtual env folder. now back to
error found at [OpenCV facemorpher 1.0.1 error: no image output, missing
library?](http://stackoverflow.com/questions/35532101/opencv-
facemorpher-1-0-1-error-no-image-output-missing-library)
|
Finding maximum of a correlation in Python
Question: I have to find the parameters theta such that:
[](http://i.stack.imgur.com/rtJnf.gif)
where r is a known vector and phi is a function that uses the parameters from
the previous iteration. How can I implement that optimization in Python?
import numpy as np
import scipy.optimize as optimize
# Gaussian function
def gaussian(x, mu, sig):
return (1/(sig*np.sqrt(2*np.pi)))*np.exp(-np.power(x - mu, 2.) / (2 * np.power(sig, 2.)))
# My observed data is a sum of two gaussians
step = 0.005
numSignals = 2
x = np.arange(0, 3+step, step)
w = np.array([0.4,0.8])
mean = np.array([0.5,0.9])
sigma = np.array([0.1,0.2])
noise = 0.05*np.random.normal(0,1,len(x))
y = w[0]*gaussian(x, mean[0], sigma[0]) + w[1]*gaussian(x, mean[1], sigma[1])
#Initialization, I assume my model is a sum of weighted gaussians and it is empty at the beginning
model = 0
i = 0
_mean = np.zeros(numSignals)
_sigma = np.zeros(numSignals)
_w = np.zeros(numSignals)
while i<numSignals:
r = y - model
# Optimization step
J = lambda c: -abs(np.dot(r,gaussian(x,c[0],c[1])))**2
res = optimize.minimize(J, (0.2, 0.5), method='TNC', tol=1e-6)
_mean[i] = res.x[0]
_sigma[i] = res.x[1]
_w[i] = np.dot(gaussian(x,_mean[i],_sigma[i]),r)/np.dot(gaussian(x,_mean[i],_sigma[i]),gaussian(x,_mean[i],_sigma[i]))
model = model + _w[i]*gaussian(x,_mean[i],_sigma[i])
print _w[i],_mean[i],_sigma[i]
i += 1
this is an initialization algorithm to find values for mean, sigma and weights
of a signal, that is a sum of two gaussian functions. After the initialization
I use another algorithm that works, but this one gets wrong values (even using
as initial values for optimize the real values instead of 0.2 and 0.5 I get
0.51 and 0.54 for mean and 2.2e-6 and 2.4e-6 for sigma).
I try to optimize the correlation between a residual (r) and the base
functions (gaussian functions) to find the estimated values (_w,_mean,_sigma)
Edit 1: I just try to find the parameters (w,mean and sigma) that maximize the
expression above (or minimize the negative in my code) so I find estimations
to initialize another algorithm. But despite using the real values as initial
values in the minimize method from scipy I get wrong values for mean and
sigma.
Edit 2: gaussian function works perfectly... so before commenting, test the
code you refer to, and don't try to humiliate people
Answer: I think there's a conceptual, SciPy-unrelated problem with your approach. If I
understand you correctly, you have data (`y` in your code) that can be
explained as the sum of two (unknown) Gaussians. (I.e., `mean` and `sigma` are
only given here because you calculate `y` for the sake of example. Usually,
`y` would be the result of some measurement.)
You now try to find the parameters of the two Gaussians by first fitting one
Gaussian to the data, and then fitting another Gaussian to the difference
between that first fit and the data (the residue, in your code `r` in the
second iteration). This might approximately give you the underlying Gaussians
if one of them was clearly dominating the data. However, in the data you
provided, both the influence of both underlying Gaussians has a similar order
of magnitude.
Thus, in the first iteration, you'll get one Gaussian that alone best
approximates the data. Because it has to 'cover' the effect of _both_
underlying Gaussians combined, it cannot be too similar to a single one of
them. Trying to then approximate the residue with another (also dissimilar)
Gaussian won't rescue you from that.
If you want to get satisfying results, you'll have to fit all parameters of
your two-Gaussian-model in one go.
|
Positioning Button in Python
Question: Ive researched my question here, [Python Tkinter
buttons](http://stackoverflow.com/questions/29370357/python-tkinter-buttons),
and here, [Setting the position on a button in
Python?](http://stackoverflow.com/questions/10927234/setting-the-position-on-
a-button-in-python)
Sadly, I'm still stuck. I'm making a game inspired by the game angry red
button.
I'm attempting to have a second button placed next to a first one, which
python autonomatically places in the top center of the screen.
When I run the code pasted below, no additional button appears. See screen
shot below, [Screen Shot ](http://i.stack.imgur.com/OYtKu.png)
Here is my attempt using pack (seen toward the bottom of the code).
from tkinter import *
s = 0
def kill():
cnv.color('red')
def talk():
global s
if s == 0:
cnv.create_text(100,20,text='why, hello there!', font='Times')
s += 1
elif s == 1:
cnv.create_text(100,40,text='my name is Phill!', font='Courier')
s += 1
elif s == 2:
cnv.create_text(100,60,text='why are you clicking me?', font='Times')
s += 1
elif s == 3:
cnv.create_text(100,80,text='that kinda hurts...', font='Arial')
s += 1
elif s == 4:
cnv.create_text(100,100,text='ok, what do you want?', font='Courier')
s += 1
elif s == 5:
cnv.create_text(145,130,text='seriously, stop that!', font=('Arial',28), fill='red')
s += 1
elif s == 6:
cnv.create_text(100,160,text='...', font='Times')
s += 1
elif s == 7:
cnv.create_text(100,180,text='You know what?', font='Courier')
s += 1
elif s == 8:
cnv.create_text(100,200,text="You wanna go?", font='Courier')
s += 1
elif s == 9:
cnv.create_text(105,220,text='OK!!!', font=('Arial',28), fill='red')
v = Button(tk, text="Death",command=kill)
v.pack(side="right")
l = Button(tk, text="Death",command=kill)
l.pack(side="left")
s += 1
tk = Tk()
btn = Button(tk, text="Phill",command=talk,width=10,height=10)
btn.pack()
cnv = Canvas(tk, width=1000, height=700)
cnv.pack()
Any ideas how to make this work with pack, or perhaps with grid?
Answer: use `.pack(side=LEFT)` for example, or whatever side you want. I suggest
experimenting with this.
|
Pip installer error
Question: I am trying to install `PyAutoGUI` but every time i try i get the error
message
C:\WINDOWS\system32>C:\Users\nicho\AppData\Local\Programs\Python\Python35-32\Scripts\pip install PyAutoGUI
Collecting PyAutoGUI
Using cached PyAutoGUI-0.9.33.zip
Collecting pymsgbox (from PyAutoGUI)
Using cached PyMsgBox-1.0.3.zip
Collecting PyTweening>=1.0.1 (from PyAutoGUI)
Using cached PyTweening-1.0.3.zip
Collecting Pillow (from PyAutoGUI)
Using cached Pillow-3.1.1-cp35-none-win32.whl
Collecting pyscreeze (from PyAutoGUI)
Using cached PyScreeze-0.1.8.zip
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\nicho\AppData\Local\Temp\pip-build-jt08_ns2\pyscreeze\setup.py", line 6, in <module>
version=__import__('pyscreeze').__version__,
File "c:\users\nicho\appdata\local\temp\pip-build-jt08_ns2\pyscreeze\pyscreeze\__init__.py", line 21, in <module>
from PIL import Image
ImportError: No module named 'PIL'
----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in C:\Users\nicho\AppData\Local\Temp\pip-build-jt08_ns2\pyscreeze
Can anyone help me?
Answer: You should install the `Python Image Library(PIL)`, using the command:
sudo pip install PIL --allow-external PIL --allow-unverified PIL
|
Saving each result on a new line to a csv file, using python
Question: I've been trying to create a csv file using python and save a new date on a
new row. My intention is to replicate the shell output(shown below), in csv
file. However the output I get is only saving the last result and iterating
through one date(shown in the csv output below). I'm sure there's an error in
my approach but I'm stumped. thanks in advance.
from datetime import timedelta, date
import csv
def daterange(start_date, end_date):
for n in range(int ((end_date - start_date).days)):
yield start_date + timedelta(n)
start_date = date(2014, 12, 28)
end_date = date(2015, 1, 10)
for single_date in daterange(start_date, end_date):
new_date = single_date.strftime("%Y-%m-%d")
with open('output.csv', 'wb') as f:
writer = csv.writer(f)
writer.writerows(new_date)
[shell output](http://i.stack.imgur.com/qg6Le.png) [csv
output](http://i.stack.imgur.com/bHTHg.png)
Answer: When you open a file with `w` mode, python truncates the file. You should open
it only once:
with open('output.csv', 'wb') as f:
writer = csv.writer(f)
for single_date in daterange(start_date, end_date):
new_date = single_date.strftime("%Y-%m-%d")
writer.writerow(new_date)
|
Pip Django Version Different than Python's
Question: I am currently trying to complete the Django tutorial found here:
<https://docs.djangoproject.com/en/1.9/intro/tutorial01/>
However, when I try to run `python manage.py migrate` I get the error `Unknown
command: 'migrate'`. I looked this up and discovered that this means I am
using a version of Django that doesn't support migrate. So I ran `python -c
"import django; print(django.get_version())"` to see what version of Django
Python was using. Turns out it's 1.6.1. This doesn't make sense though because
when I do `pip list` I get Django (1.9.2). If I look in my settings.py file it
even says "Generated by 'django-admin startproject' using Django 1.9.1."
Does anyone know why Python is using a different version of Django than is
installed using pip?
Answer: It's highly recommended that you run Django in a virtual environment as it
will make managing Django a lot easier, and you don't want to mess with the
python version on your system.
use `virtualenv -p /usr/bin/python3.5 <path/to/new/virtualenv/>` to use
virtualenv with a specific python version.
Then `pip install Django` to get the latest version of Django.
**Edit:**
Don't forget that when you're messing with Django settings and files, that you
need to activate your virtualenv in your command prompt.
Type `source myprojectenv/bin/activate` and your prompt should change to
`(myprojectenv)user@host:~/myproject$`
|
What is "empty" expression in django rest_framework.serializers.BaseSerializer
Question: Here is the `__init__` method in django's
`rest_framework.serializers.BaseSerializer` class.
def __init__(self, instance=None, data=empty, **kwargs):
self.instance = instance
if data is not empty:
self.initial_data = data
self.partial = kwargs.pop('partial', False)
self._context = kwargs.pop('context', {})
kwargs.pop('many', None)
super(BaseSerializer, self).__init__(**kwargs)
By default `data=empty`. `empty` is not imported or defined anywhere in
`serializers.py`. And I never saw this before in python (Im still beginner
tho).
How does `empty` work here? From the first look to me it seems that `empty` is
an undefined variable here.
Answer: `empty` is defined in `rest_framework.fields`:
<https://github.com/tomchristie/django-rest-
framework/blob/master/rest_framework/fields.py#L39>.
It can be used in the place that you mention because it's being imported at
line 46: <https://github.com/tomchristie/django-rest-
framework/blob/master/rest_framework/serializers.py#L46>.
|
Year over year matplotlib with legend
Question: I'm trying to mimic this graph from Excel [](http://i.stack.imgur.com/P2WLQ.png)
in python and matplotlib.
The dataframe (by_year) looks below with a multiindex of EDIT - Changed table
to reflect that the rows are different
Month 1 2 3 4 5 6 7 8 9 10 11 12
Year
2012 8 6 8 9 1 2 8 9 4 3 2 6
2013 5 6 2 9 6 2 8 9 4 3 2 6
2014 7 6 3 9 4 2 8 9 4 3 2 6
# create multiple plots on the page (i'm going to print this rather
# than display live
ax1 = plt.subplot2grid((3, 2), (0,0), colspan=2)
ax2 = plt.subplot2grid((3, 2), (1,0))
# loop through the years (each row) and add to chart
for idx, row in by_year.iterrows():
row_values = row.values.astype(int).tolist()
ax1.bar(month_list, row_values)
ax1.legend(str(idx))
Problem 1 - This runs with no errors, however i only get a single set of bars.
Don't understand how to fix this. Graph looks like this: [](http://i.stack.imgur.com/oonbr.png)
EDIT - Problem is in the ax1.bar(month_list... line. It uses the same starting
point for each row and hence the bars are on top of each other. The solution
below by @GWW calculates the start position using idx. Which i would really
name bar_start.
Problem 2 - I can't find anywhere how to add that legend with the data under
the table. I can try and create by simply displaying the dataframe (i think :)
) but does Matplotlib already have the functionality?
Answer: This should get you started. You will still have to fiddle around with the
table properties to make it look better.
[](http://i.stack.imgur.com/Hsqt9.png)
months = [1,2,3,4,5,6,7,8,9,10,11,12]
by_year = [
(2012, (8,6,8,9,1,2,8,9,4,3,2,6)),
(2013, (5,6,2,9,6,2,8,9,4,3,2,6)),
(2014, (7,6,3,9,4,2,8,9,4,3,2,6)),
]
colors = ['r','g','b','y']
import pylab as plt
fig, ax = plt.subplots(1,1, figsize=(8, 4))
#0.9 to leave a small space between groups of bars
import numpy as NP
N = 0.95 / (len(by_year))
cell_text = []
for i, (year, row) in enumerate(by_year):
print i, year, row
idx = NP.arange(0, len(months)) + N * i
# * 0.8 to put a small gap between bars
ax.bar(idx, row, color=colors[i], width=N * 0.8, label=year)
cell_text.append(row)
tbl = ax.table(cellText=cell_text, rowLabels=[x[0] for x in by_year], loc='bottom', colLabels=months)
prop = tbl.properties()
ax.set_xticks([])
lgd = ax.legend(loc='upper left', bbox_to_anchor=(1, 1.0))
fig.show()
|
Bigram Count using Spark (Python) producing strange output
Question: I am trying to do a bigram count using Spark, Python API.
I am getting strange output. Multiple lines of:
generator object genexpr at 0x11aab40
This is my code:
from pyspark import SparkConf, SparkContext
import string
conf = SparkConf().setMaster('local').setAppName('BigramCount')
sc = SparkContext(conf = conf)
RDDvar = sc.textFile("file:///home/cloudera/Desktop/smallTest.txt")
sentences = RDDvar.flatMap(lambda line: line.split("."))
words = sentences.flatMap(lambda line: line.split(" "))
bigrams = words.flatMap(lambda x:[((x[i],x[i+1]) for i in range(0,len(x)-1))])
result = bigrams.map(lambda bigram: bigram, 1)
aggreg1 = result.reduceByKey(lambda a, b: a+b)
result.saveAsTextFile("file:///home/cloudera/bigram_out")
What is going wrong?
Answer: Python seems to be storing the generator expressions as variables in the line:
bigrams = words.flatMap(lambda x:[((x[i],x[i+1]) for i in range(0,len(x)-1))])
You probably just need to replace this with something like:
bigrams = words.flatMap( lambda x:list((x[i],x[i+1]) for i in range(0,len(x)-1)) )
see [here](http://stackoverflow.com/questions/5164642/python-print-a-
generator-expression) for a more in-depth explanation.
|
Tell compiler about a local it doesn't know about?
Question: I have a function called `let`, which modifies the calling namespace to insert
a new variable.
def let(**nameValuePair):
from inspect import stack
name, value = nameValuePair.items()[0]
stack()[1][0].f_locals[name] = value
return value
The idea is it allows you insert assignment statements anywhere you want, even
where assignment statements aren't typically allowed in Python (albeit, it
requires 5 extra characters for `let()`.
This works perfectly when called from the global namespace.
>>> let(outside = 'World')
>>> print(outside)
World
This fails with the error `NameError: global name 'hello' is not defined`:
>>> def breaker():
... let(hello = 'World')
... print(hello)
...
>>> breaker()
You might jump to the conclusion that the issue is with my `let` function. It
is not - my function performs perfectly. To show you that:
>>> def fine():
... let(another = 'World')
... print(locals()['another'])
...
>>> fine()
World
The issue actually comes from when the Python interpreter compiles `breaker`.
To demonstrate, I'll create another function which does the same thing as
`breaker`, but using an ordinary assignment instead of `let`, and then I'll
decompile both with `dis`.
>>> def normal():
... hello = 'World'
... print(hello)
...
>>> normal()
World
>>> from dis import dis
>>> print(dis(normal))
0 LOAD_CONST 1 ('World')
3 STORE_FAST 0 (hello)
6 LOAD_FAST 0 (hello)
9 PRINT_ITEM
10 PRINT_NEWLINE
11 LOAD_CONST 0 (None)
14 RETURN_VALUE
>>> print(dis(breaker))
0 LOAD_GLOBAL 0 (let)
3 LOAD_CONST 1 ('hello')
6 LOAD_CONST 2 ('World')
9 CALL_FUNCTION 256
12 POP_TOP
13 LOAD_GLOBAL 2 (hello) # <= This is the real problem.
16 PRINT_ITEM
17 PRINT_NEWLINE
18 LOAD_CONST 0 (None)
19 RETURN_VALUE
The problem is, the compiler is looking over `breaker`, doesn't see that
`hello` gets assigned anywhere in the local scope, and so assumes that it must
be a global variable.
What can I do about this? When my function gets called, could I, for example,
swap out the problematic line that I indicated and replace it with:
LOAD_GLOBAL 1 (locals)
CALL_FUNCTION 0
LOAD_CONST 1 ('hello') # Or whatever the name of the variable is
BINARY_SUBSCR
I know that I could quickly fix the immediate problem by simply storing the
variable in the global scope, but that could lead to lots of subtle bugs. To
name a few:
1. Global variables get written over.
2. Objects might persist in memory for far longer than intended.
3. Something that would be a typo otherwise, is instead valid. (admittedly this one seems quite unlikely).
... Actually, if I can change the compiled code, I could even add a
`STORE_GLOBAL` or `DELETE_GLOBAL` after `RETURN_VALUE`, perhaps? Cache the
former global variable elsewhere or something?
Answer: The documentation for `locals()` notes the following:
> **Note** The contents of this dictionary should not be modified; changes may
> not affect the values of local and free variables used by the interpreter.
I checked and don't see an explicit note in the `inspect` docs about
`f_locals` but I don't see why it would be any different.
|
Python multiple pattern matching from a log file
Question: I've got a log file with following format:
2016-02-18 10:01:45.423 [a-b] [one two three] [2126]
2016-02-18 10:01:45.623 [x-y] [one two three four] [123]
2016-02-18 10:01:45.823 [z-w] [one two three four-five] [0]
I'd like to split the fields into variables so that e.g. for the first line:
Field1 = 2016-02-18
Field2 = 10:01:45.423
Field3 = a-b
Field4 = one two three
Field5 = 2126
I'm trying to figure out how to get the two first fields as I managed to get
the last 3 with the following:
>>> import re
>>> data = """2016-02-18 10:01:45.423 [a-b] [one two three] [2126]"""
>>> PATTERN = re.compile(r'''\[(.*?)\]''')
>>> print (PATTERN.split(data)[1::2])
['a-b', 'one two three', '2126']
>>>
The content of the "Field4" may vary in length and the separator between
Field2 and Field3 is 2x white space.
How do I change the code above to capture each field?
Thanks!
Answer: It can be done without regular expression also:
with open("your_log.log") as f:
for x in f:
fields = x.strip().split()
field1, filed2, field3, field4, field5 = fields[0], fields[1], fields[2], " ".join(fields[3:-1]), fields[-1]
|
Error in generating colored cmy qr image
Question: I have to generate 3 QR images with background color cyan, magenta and yellow
and merge them to generate CMY colored QR as shown in image 1. Now after
generating images, to merge them by using cv2.merge,converting these into gray
image and then merging operation gives me image 2 instead of image 1 (Ignore
the color of finder patterns) I am using Python 2.7, Open CV 3.0. Unable to
figure out what I am doing wrong. Please help me to get out of this. Thanks in
advance.
[](http://i.stack.imgur.com/Ju9WV.png)
[](http://i.stack.imgur.com/eeXEJ.png)
Code I am using is given below:
import pyqrcode
import cv2
bigcode = pyqrcode.create('When I say it is you', error='L', version=2,mode='binary')
bigcode.png('new1.png', scale=6, module_color=[0, 0, 0], background = [0xff,0xff,0])
bigcode1 = pyqrcode.create('peace that triumphant over war ', error='L', version=2, mode='binary')
bigcode1.png('new2.png', scale=6, module_color=[0, 0, 0], background = [0xff,0,0xff])
bigcode2 = pyqrcode.create('Love that conquers hate ', error='L', version=2, mode='binary')
bigcode2.png('new3.png', scale=6, module_color=[0, 0, 0], background = [0,0xff,0xff])
bigcode.show()
b = bigcode1.show()
c = bigcode2.show()
img1 = cv2.imread('C:/New folder (2)/new1.png')
img2 = cv2.imread('C:/New folder (2)/new2.png')
img3 = cv2.imread('C:/New folder (2)/new3.png')
gray_img1 = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)
cv2.imshow('k1',gray_img1)
gray_img2 = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)
gray_img3 = cv2.cvtColor(img3, cv2.COLOR_BGR2GRAY)
k = cv2.merge([gray_img1,gray_img2,gray_img3])
cv2.imshow('k',k)
cv2.imwrite('k.png',k)
cv2.waitKey(0)
Answer: Instead of generating c,m,y,k colored QR, try to convert rgb in cmyk
colorspace. this would help in generating correct result.
|
Detect URLs changes in python
Question: I need to detect urls changes when shops have a firesale on, I'm using
requests lib with no luck even when a firesale is on it still returns `No
deals on today` and check value is still `[u'http:', u'',
u'www.dealwebsite.co', u'Electroshop']`
primary shop url `http://www.dealwebsite.com/coolshop`
if firesale deals are on the primary shop url changes to this like a redirect
`http://www.dealwebsite.com/coolshop/firesale`
import requests
headers = {
'User-Agent': 'Mozilla\/5.0 (Windows NT 6.1; WOW64) AppleWebKit\/537.36 (KHTML, like Gecko) Chrome\/45.0.2454.101 Safari\/537.36'
}
select_shop = 'Electroshop'
url = 'http://www.dealwebsite.co/' + select_shop
r = requests.get(url, headers=headers, timeout=3)
check = r.url.split('/')
if len(check) != 5:
print 'No deals on today'
exit()
else:
print 'Firesale Deals on NOW!'
Answer: It seems that you can [track redirection](http://docs.python-
requests.org/en/master/user/quickstart/#redirection-and-history). For example:
requests.get(url, headers=headers, timeout=3, allows_redirect=True)
>>> r.url
'url'
>>> r.status_code
200
>>> r.history
[<Response [301]>] # means that there was a redirect on the way
Actually, you could use just a HEAD request to verify the behavior - only if
you don't need to parse the result (as a HEAD response body is empty).
>>> r = requests.head(url, headers=headers, timeout=3, allow_redirects=True)
>>> r.url
'..something...'
>>> r.history
[<Response [301]>]
In theory, you could also prevent the redirect completely, and check for the
response status.
>>> r = requests.get(url, headers=headers, timeout=3, allow_redirects=False)
>>> r.status_code
301
>>> r.history
[]
Now, 301 might mean a redirect to firesale or somewhere else - you don't know.
**UPDATE 1**
An example with periscope.tv (it seems that the OP has issues with such a
website):
>>> example = requests.get("https://periscope.tv/couchmode", allow_redirects=True)
>>> example.status_code
200
>>> example.history
[<Response [307]>]
>>> example.history[0].url
u'https://periscope.tv/couchmode'
>>> example.url
u'https://periscope.tv/w/aZwcYHNlcnZpY2V8MURYeHl6WUFaUWdLTerSfgniRKoRgIPbfxxlbAGofYQNBd8WZZTEelJ0KavI?mode=couch'
As you can see, example.history[0].url tells you what was the URL that
returned a 307 temporary redirect.
|
Path in the PYTHONPATH not in django path
Question: I am writing a web based app based on python and django. I have a source code
folder containing **LIBS** directory that has a file named **utils.py**. When
I want to install my app a new line is added to ~/.profile file like **export
PYTHONPATH=$PYTHONPATH:/home/test/src/LIBS** (The path is added based on the
installation path) When I run the below code in the interpreter the path is
OK:
import sys
sys.path
> ['', '/usr/lib/python2.7', '/home/test/src/LIBS',
> '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk',
> '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload',
> '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-
> packages', '/usr/lib/pymodules/python2.7']
Unfortunately, when i want to load the home page of my app the line that
imports **utils** raises an exception [](http://i.stack.imgur.com/dPayE.png)
What i do wrong? Thanks in advanced.
Answer: Your ~/.profile only adds the dir to the PYTHONPATH in the current shell
environment. It's not globally available. When django loads, it uses the
wsgi.py and another project path.
The easiest way to add a globally available path is to add a .pth file. It
should be in your python dist-packages directory (depends on the OS):
$ sudo nano /usr/lib/python2.7/dist-packages/
/home/test/src/LIBS
And save the file.
Now the app will be available for all python instances on your machine.
If you want to add this path only to a specific django project, in the wsgi.py
add:
import sys
sys.path.append("/home/test/src/LIBS")
|
StopIteration error in python
Question: I am using `wolframalpha` and `wit.ai` together and i am trying to build that
`wolframalpha` fetch data from `wit.ai` audio instead of terminal text.
My code is:
#!/usr/bin/python
import speech_recognition as sr
import wolframalpha
import sys
r = sr.Recognizer()
with sr.Microphone() as source:
print("Say something!")
audio = r.listen(source)
WIT_AI_KEY = "NQYEITRO5GL2Q2MZFIJE4UHWVNQEUROW"
try:
print("Wit.ai thinks you said " + r.recognize_wit(audio, key=WIT_AI_KEY))
except sr.UnknownValueError:
print("Wit.ai could not understand audio")
except sr.RequestError as e:
print("Could not request results from Wit.ai service; {0}".format(e))
client = wolframalpha.Client('PR5756-H3EP749GGH')
print(r.recognize_wit(audio, key=WIT_AI_KEY))
res = client.query(r.recognize_wit(audio, key=WIT_AI_KEY))
print(next(res.results).text)
I am facing this error:
MacBook-Air:Documents exepaul$ python ak.py
2016-02-22 23:05:04.429 Python[3003:122880] 23:05:04.428 WARNING: 140: This application, or a library it uses, is using the deprecated Carbon Component Manager for hosting Audio Units. Support for this will be removed in a future release. Also, this makes the host incompatible with version 3 audio units. Please transition to the API's in AudioComponent.h.
Say something!
Wit.ai thinks you said seven
seven
Traceback (most recent call last):
File "ak.py", line 24, in <module>
print(next(res.results).text)
StopIteration
How can I give data to wolframalpha api?
Answer: `StopIteration` is raised when generator is exhausted and has no more values,
it's totaly ok to get one. But you need to handle it yourself:
try:
print(next(res.results).text)
except StopIteration:
print("No more suggesstions.")
|
injecting variables into functions; python
Question: I have a webdriver class that assumes there is only one driver. This is bad
because it can't handle multiple pages at once. I want to make a decorator
that will inject `self.driver` into any function decorated if it exists, if
not it will allow any function to use the driver passed to it. I should be
able to define and function as
@get_driver
def this_func(**kwargs):
#I have access to 'driver' if I have self.driver or if a driver kwarg was given
Here it is:
import os, time, subprocess, random
from functools import wraps
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.select import Select
from pyvirtualdisplay import Display
class get_driver(object):
def __init__(self, func):
self.func = func
wraps(func)(self)
def __call__(self, *args, **kwargs):
try:
kwargs.update({'driver': self.driver})
except:
pass
return_ = self.func(*args, **kwargs)
return return_
class WebdriverChauffuer(object):
def __init__(self, username=None, password=None, start_url=None):
self.username = username
self.password = password
self.start_url = start_url
@get_driver
def source_code(self, **kwargs):
return driver.page_source or None
class FirefoxDriver(WebdriverChauffuer):
def __init__(self, username=None, password=None, start_url=None, driver=None):
super(FirefoxDriver, self).__init__(username=username, password=password, start_url=start_url)
def start_driver(self):
self.driver = webdriver.Firefox()
I am getting a strange error that no args were given, even though I call
`source_code` on an instance, which should give it self:
In [1]: from my_scripting_library import *
In [2]: d = FirefoxDriver()
In [3]: d.start
d.start_driver d.start_url
In [3]: d.start_driver()
In [4]: d.get('https://google.com')
In [5]: d.source_code()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-5-7419cf5df019> in <module>()
----> 1 d.source_code()
/home/cchilders/scripts/my_scripting_library/webdriver/general.pyc in __call__(self, *args, **kwargs)
24 except:
25 pass
---> 26 return_ = self.func(*args, **kwargs)
27 return return_
28
TypeError: source_code() takes exactly 1 argument (0 given)
There's no difference when I change the return to
return_ = self.func(**kwargs)
Why can't I call `source_code` anymore? Thank you
EDIT:
These drivers are to be used for purposes of course, here's an example:
class HCCDriver(FirefoxDriver):
def __init__(self, init=False):
super(HCCDriver, self).__init__(start_url="https://hccadvisor.hccfl.edu")
def main_page(self):
self.get('https://www.hccfl.edu/hawknet.aspx')
def login_webadvisor(self, username="cchilders", password="miley_cirus_is_great_singer", driver=None):
self.webadvisor_driver = FirefoxDriver()
webadvisor_driver.get(self.start_url)
time.sleep(2)
driver.access_link(search_text="Log In")
driver.find_box_and_fill(search_text="LABELID_USER_NAME", value=username)
driver.find_box_and_fill(search_text="CURR.PWD", value=password)
driver.submit_form(search_text="SUBMIT")
driver.access_link(search_text="Students")
def login_email(self):
self.start_driver()
self.get("http://outlook.com/hawkmail.hccfl.edu")
# WebDriverWait(self.driver, 10).until(EC.presence_of_element_located(By.ID, 'ctl00_ContentPlaceHolder1_UsernameTextBox'))
self.find_box_and_fill(search_text="ctl00_ContentPlaceHolder1_UsernameTextBox", value="[email protected]")
self.find_box_and_fill(search_text="ctl00_ContentPlaceHolder1_PasswordTextBox", value="i_love_honey_booboo")
time.sleep(2)
self.submit_form("ctl00_ContentPlaceHolder1_SubmitButton")
def login_myhcc(self):
driver = FirefoxDriver()
driver.get("https://hcc.instructure.com")
time.sleep(5)
find_box_and_fill('ctl00_ContentPlaceHolder1_UsernameTextBox', '[email protected]')
driver.find_box_and_fill('ctl00_ContentPlawebadvisor_urlceHolder1_PasswordTextBox', 'if_evolution_was_real_americans_would_stop_worshipping_pres_candidates')
driver.click_button('ctl00$ContentPlaceHolder1$SubmitButton')
The point is, without a decorator, I foresaw every single function looking
like:
def this_func(self, driver=None):
if not driver:
try:
driver = self.driver
except:
raise Exception('There is no driver my good sir')
with the `driver=None` and
try:
driver = self.driver
except:
raise Exception('There is no driver good sir')
parts being repetitive 20, 30 times, etc
Answer: Because your decorator is implemented as a class rather than a function, your
decorated `source_code` function is not being wrapped in a bound `method`
descriptor, since this is done to functions, not classes.
That means when you call `self.func`, no `self` argument is being passed in.
But your `source_code` method expects a `self` argument, which results in the
error `source_code() takes exactly 1 argument (0 given)`
On more recent versions of Python 3 you should be getting `foo() missing 1
required positional argument: 'self'`. I'm not sure when they added that
clarified message.
The comments have given you some ideas about different approaches, but that
explains your error.
|
PySide: QAbstractItemModel not talking to simple controls
Question: Using PySide, I am trying to connect several data controls to data from a file
that I read from disc. So I made a data model, derived from
QAbstractItemModel. Should be trivial, right? But one problem that has me
beaten is connecting QLineEdit and QTextEdit controls to show and allow
editing of the data in the model.
From examples such as the Simple Widget Mapper and the Combo Widget Mapper in
the QT documentation, I believe I have to have a data model with one row, and
a QWidgetMapper to connect the cells in that row to the edit controls.
Here is a very cut-down program that shows the problem. The data model in this
example returns the three strings x1, x2 and x3. The strings are changed from
e.g. "First (1)" to "First (2)" by calling Update, i.e. by clicking the "Next"
button. That is to simulate new values being read from a file or wherever. The
main window has a couple of QLineEdits and a QTextEdit, which the mapper
should link to the model data. But the data don't show up in the edit
controls.
To check the model, I added a QTableView. The data show up there alright, and
update when "Next" is clicked, so it's not the data model. It's something
between there and the edit controls. But I cannot see what I am not doing,
that the widget mapper examples are doing.
What am I doing wrong?
Incidentally, going the other way doesn't work well either. If I add a
setData() method to the model, and emit dataChanged, a change typed into the
line edit gets to the Table. But even when that happens, the item disappears
from the line edit. And after "Next" is clicked, this stops working for the
QLineEdit and QTextEdit -- setData() no longer gets called. But if I edit in
the table view, setData is still called.
Here is the example code:
#!/usr/bin/python
import sys
from PySide.QtCore import ( Qt, QAbstractItemModel,QModelIndex
)
from PySide.QtGui import ( QApplication, QMainWindow, QPushButton, QWidget,
QTextEdit, QLineEdit, QFormLayout, QTableView,
QDataWidgetMapper,
)
##############################################################################
class TModel(QAbstractItemModel):
"""
This model will have 1 row of 3 items
There will be a slot that will change the items. If they are displayed
in widgets, I want to see them update.
"""
def __init__(self, parent=None):
super(TModel, self).__init__(parent)
self.counter = 0
self.x1 = ""
self.x2 = ""
self.x3 = ""
self.Update()
def columnCount(self, index=QModelIndex()):
return 3
def rowCount(self, index=QModelIndex()):
return 1
def index(self, row, column, index=QModelIndex()):
if not self.hasIndex(row, column, index):
return QModelIndex()
return self.createIndex(row, column)
def parent(self, index):
return QModelIndex()
def hasChildren(self, index):
return False
def data(self, index, role=Qt.DisplayRole):
if index.isValid():
if role == Qt.DisplayRole:
if index.column() == 0:
return self.x1
elif index.column() == 1:
return self.x2
elif index.column() == 2:
return self.x3
return None
def headerData(self, section, orientation, role):
if role != Qt.DisplayRole:
return None
if orientation == Qt.Horizontal:
if section == 0:
return "col 1"
elif section == 1:
return "col 2"
elif section == 2:
return "col 3"
def Update(self):
self.beginResetModel()
self.x1 = "First (%d)"%self.counter
self.x2 = "Second (%d)"%self.counter
self.x3 = "Third (%d)"%self.counter
self.counter += 1
self.endResetModel()
##############################################################################
class TMainWindow(QMainWindow):
"""Main GUI object"""
def __init__(self, parent=None):
super(TMainWindow, self).__init__(parent)
self.DataModel = TModel()
self.Mapper = QDataWidgetMapper()
self.Mapper.setSubmitPolicy(self.Mapper.AutoSubmit)
self.Mapper.setModel(self.DataModel)
self.FirstFieldEdit = QLineEdit()
self.SecondFieldEdit = QLineEdit()
self.ThirdFieldEdit = QTextEdit()
self.Mapper.addMapping(self.FirstFieldEdit, 0)
self.Mapper.addMapping(self.SecondFieldEdit, 1)
self.Mapper.addMapping(self.ThirdFieldEdit, 2)
self.Mapper.toFirst()
self.UpdateButton = QPushButton("Next")
self.UpdateButton.clicked.connect(self.DataModel.Update)
formLayout = QFormLayout()
formLayout.addRow("&First:", self.FirstFieldEdit)
formLayout.addRow("&Second:", self.SecondFieldEdit)
formLayout.addRow("&Third:", self.ThirdFieldEdit)
formLayout.addRow("", self.UpdateButton)
self.testTable = QTableView()
self.testTable.setModel(self.DataModel)
formLayout.addRow("Table:", self.testTable)
W = QWidget()
W.setLayout(formLayout)
self.setCentralWidget(W)
##############################################################################
if __name__ == "__main__":
app = QApplication(sys.argv)
MainWindow = TMainWindow()
MainWindow.show()
sys.exit(app.exec_())
Answer: The `QDataWidgetMapper` class is intended to allow displaying and editing
records in a model. But your model doesn't return anything when data is
requested for editing. So a simple fix would be:
def data(self, index, role=Qt.DisplayRole):
if index.isValid():
if role == Qt.DisplayRole or role == Qt.EditRole:
...
**EDIT** :
From the Qt Docs:
> QDataWidgetMapper can be used to create data-aware widgets by mapping them
> to **sections** of an item model. A section is a **column** of a model if
> the orientation is horizontal (the default), otherwise a **row**. [emphasis
> added]
I would suggest you avoid trying to write a custom model (which is very far
from trivial, except for the simplest of cases), and start by using a
[QStandardItemModel](http://doc.qt.io/qt-5/qstandarditemmodel.html).
|
Python3 filling a dictionary concurrently
Question: I want to fill a dictionary in a loop. Iterations in the loop are independent
from each other. I want to perform this on a cluster with thousands of
processors. Here is a simplified version of what I tried and need to do.
import multiprocessing
class Worker(multiprocessing.Process):
def setName(self,name):
self.name=name
def run(self):
print ('In %s' % self.name)
return
if __name__ == '__main__':
jobs = []
names=dict()
for i in range(10000):
p = Worker()
p.setName(str(i))
names[str(i)]=i
jobs.append(p)
p.start()
for j in jobs:
j.join()
I tried this one in python3 on my own computer and received the following
error:
..
In 249
Traceback (most recent call last):
File "test.py", line 16, in <module>
p.start()
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/process.py", line 105, in start
In 250
self._popen = self._Popen(self)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/context.py", line 212, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/context.py", line 267, in _Popen
return Popen(process_obj)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/popen_fork.py", line 20, in __init__
self._launch(process_obj)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/multiprocessing/popen_fork.py", line 66, in _launch
parent_r, child_w = os.pipe()
OSError: [Errno 24] Too many open files
Is there any better way to do this?
Answer: `multiprocessing` talks to its subprocesses via pipes. Each subprocesses
requires two open file descriptors, one for read and one for write. If you
launch 10000 workers, you'll end opening 20000 file descriptors which exceeds
the default limit on OS X (which your paths indicate you're using).
You can fix the issue by raising the limit. See
<http://superuser.com/questions/433746/is-there-a-fix-for-the-too-many-open-
files-in-system-error-on-os-x-10-7-1> for details - basically, it amounts to
setting two sysctl knobs and upping your shell's ulimit setting.
|
Does Python IDE have a module which imports math functions such as cos or sin?
Question: Currently, I'm working on a program which takes some user input and uses this
information to work out a question e.g cos50 or anything like that. I'm not
entirely sure if python has a module which allows these sorts of equations
however so I was wondering if anyone knows about one. An example of my coding
can be found below:
# SINE AND COSINE CALCULATOR #
loop = True
while loop == True:
UserInput = input("Would you like to work out Sine or Cosine rule?")
UserInputCaps = UserInput.upper()
if "COSINE" in UserInputCaps:
D = input("Enter the value of the paired angle:")
a = float(input("Enter the value of length A"))
b = float(input("Enter the value of length B"))
c = (a**2) + (b**2) - (2*a*b)* cos(D)
print(c)
if "SINE" in UserInputCaps:
a = input("Please enter the length")
A = input("Please enter the angle")
b = input("Please enter the other angle")
ans = (a / sin(A)) * sin(b)
print(ans)
Answer: Python's [`math`](https://docs.python.org/2/library/math.html) module:
A simple Google search would have helped.
|
Caffe : cifar 10_quick testing issue
Question: I have trained CIFAR QUICK using caffe, but when I test the
cifar10_quick_iter_5000.caffemodel.h5 using a python wrapper I get an accuracy
around 52-54% whereas it should be 75%. I do not understand why I am geting
such a low accuracy, because when I test Lenet MNIST I get the expected
accuracy as per the MNIST example in caffe website. To verify if my method is
right or wrong I have tried the cifar trained model file from
[Clasificador_Cifar-10](https://github.com/IsaacRocos/Clasificador_Cifar-10.git)
and I get and accuracy of 68%.
Please let me know if I am missing something when I test the model.
import sys
import caffe
import cv2
import Image
import matplotlib
import numpy as np
import lmdb
caffe_root = '/home/fred/CIFAR_QUICK/caffe'
MODEL_FILE = '/home/fred/CIFAR_QUICK/caffe/examples/cifar10/cifar10.prototxt'
PRETRAINED = '/home/fred/CIFAR_QUICK/caffe/examples/cifar10/cifar10_60000.caffemodel.h5'
net = caffe.Net(MODEL_FILE, PRETRAINED,caffe.TEST)
caffe.set_mode_cpu()
db_path = '/home/fred/CIFAR_QUICK/caffe/examples/cifar10/cifar10_test_lmdb'
lmdb_env = lmdb.open(db_path)
lmdb_txn = lmdb_env.begin()
lmdb_cursor = lmdb_txn.cursor()
count = 0
correct = 0
for key, value in lmdb_cursor:
print "Count:"
print count
count = count + 1
datum = caffe.proto.caffe_pb2.Datum()
datum.ParseFromString(value)
label = int(datum.label)
image = caffe.io.datum_to_array(datum)
image = image.astype(np.uint8)
out = net.forward_all(data=np.asarray([image]))
predicted_label = out['prob'][0].argmax(axis=0)
print out['prob']
if label == predicted_label:
correct = correct + 1
print("Label is class " + str(label) + ", predicted class is " + str(predicted_label))
print(str(correct) + " out of " + str(count) + " were classified correctly")
Answer: See my answer [here](http://stackoverflow.com/a/35572495/3579977). You are not
subtracting the mean which results in low accuracy. The link to the code,
posted above, takes care of that. Apart from this there's nothing wrong with
your approach.
|
Reading serial AMA0 of Arduino writes an empty data
Question: I am connected Arduino to the Raspberry via **/dev/ttyACM0**. Despite the
python script I want to retrieve data from the Arduino, which is doing, but if
you want the data to appear more frequently (1-4 seconds) and the data does
not list any. Data is written out irregularly me, which I do not understand :(
Arduino code:
void setup() {
Serial.begin(9600);
}
void loop() {
Serial.print("25.78"); // temperature Β°C
delay(1000);
Serial.println();
}
Raspberry, python code:
import serial
serialport = serial.Serial("/dev/ttyAMA0", 9600, timeout=0.7)
response = serialport.readline()
print response
serialport.close()
Here is an excerpt:
pi@raspberrypi:~ $ python test.py
pi@raspberrypi:~ $ python test.py
pi@raspberrypi:~ $ python test.py
pi@raspberrypi:~ $ python test.py
25.78
pi@raspberrypi:~ $ python test.py
25.78
pi@raspberrypi:~ $ python test.py
25.78
pi@raspberrypi:~ $ python test.py
pi@raspberrypi:~ $ python test.py
I do not know how I could fix it to be 100% functional?
Answer: It looks like your read timeout (0.7s) is smaller than the frequency that you
write the data (every 1000ms). So if you repeatedly execute the script that
reads it, you'll sometimes miss the data. I'd recommend to either increase
your read timeout, or decrease the interval that the Arduino sleeps.
|
Designing an FIR notch filter with python
Question: I am writing some code with Python using the scipy.signal library to filter
electromagnetic data that is mixed with various undesirable signatures that I
want to filter out. For example, I have power line harmonics at various
frequencies (i.e. 60, 120 Hz, etc....) with a width of only a few Hz that I
would like to remove from the data using a notch filter. Is there already an
existing function in python where I can merely inform the code how many data
points i wish to use for the filter, the center-line frequency that I wish to
remove and the width of the transition band or do I need to design a filter
from scratch? If it is the latter I would greatly appreciate an example of
notch filter design in Python to include window implementation to minimize
aliasing.
Answer: There are a few options for the solution on the scipy.signal website, but they
introduce allot of ringing, which will translate to artifacts in the convolved
signal. After trying many things I found the following function worked the
best for implementing an FIR notch filter.
# Required input defintions are as follows;
# time: Time between samples
# band: The bandwidth around the centerline freqency that you wish to filter
# freq: The centerline frequency to be filtered
# ripple: The maximum passband ripple that is allowed in db
# order: The filter order. For FIR notch filters this is best set to 2 or 3,
# IIR filters are best suited for high values of order. This algorithm
# is hard coded to FIR filters
# filter_type: 'butter', 'bessel', 'cheby1', 'cheby2', 'ellip'
# data: the data to be filtered
def Implement_Notch_Filter(time, band, freq, ripple, order, filter_type, data):
from scipy.signal import iirfilter
fs = 1/time
nyq = fs/2.0
low = freq - band/2.0
high = freq + band/2.0
low = low/nyq
high = high/nyq
b, a = iirfilter(order, [low, high], rp=ripple, btype='bandstop',
analog=False, ftype=filter_type)
filtered_data = lfilter(b, a, data)
return filtered_data
|
Subsets and Splits