After invoking Python from within Windows Powershell, I am unable to open files in the current working directory. 

```
PS C:\python27> python
Python 2.7.9 (default, Dec 10 2014, 12:24:55) [MSC v.1500 32 bit (Intel
Type "help", "copyright", "credits" or "license" for more information.

```

After that, I type: 

```
 x = open(ex15_sample.txt)

```

With the idea of calling the open function on the filename parameter of the text file I would like to open in Python. The idea is that I can then run the following code in Windows Powershell and open that file in Python through Powershell:

```
print x.read() 

```

However I can't get to this step, because after I typed 

```
x = open(ex15_sample.txt)

```

Powershell outputs the following: 

```
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'ex15_sample' is not defined

```

In order to open the file "ex15\_sample.txt" in Python via Powershell I also typed:

```
import ex15_sample.txt

```

After reading online that this can work, but Powershell outputted the following:

```
File "<stdin>", line 1, in <module>
ImportError: No module named ex15_sample.txt

```

How can I open the file "ex15\_sample.txt" from within Python via the Powershell Command Line Interface?