most of the code examples in the book are shown with input and output as it would appear executed in the ipython shell in [ ]code out[ ]output at timesfor claritymultiple code examples will be shown side by side these should be read left to right and executed separately in [ ]code out[ ]output in [ ]code out[ ]output data for examples data sets for the examples in each are hosted in repository on githubhttp//github com/pydata/pydata-book you can download this data either by using the git revision control command-line program or by downloading zip file of the repository from the website have made every effort to ensure that it contains everything necessary to reproduce the examplesbut may have made some mistakes or omissions if soplease send me an -mailwesmckinn@gmail com import conventions the python community has adopted number of naming conventions for commonlyused modulesimport numpy as np import pandas as pd import matplotlib pyplot as plt this means that when you see np arangethis is reference to the arange function in numpy this is done as it' considered bad practice in python software development to import everything (from numpy import *from large package like numpy jargon 'll use some terms common both to programming and data science that you may not be familiar with thushere are some brief definitionsmunge/munging/wrangling describes the overall process of manipulating unstructured and/or messy data into structured or clean form the word has snuck its way into the jargon of many modern day data hackers munge rhymes with "lungenavigating this book www it-ebooks info