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I am using Python 3.2 on Windows 7. When I open the Python shell, how can I know what the current directory is? How can I change it to another directory (where my modules are)?

3
  • This has already been discussed [here] [1]: stackoverflow.com/questions/431684/how-do-i-cd-in-python Commented Nov 23, 2011 at 20:11
  • 5
    @astay13 -- I think Ignacio means that you aren't intended to change directory to your module-path. You should probably check out the PYTHONPATH environment variable. Commented Nov 23, 2011 at 20:12
  • 1
    Classical XY problem Commented May 21, 2021 at 7:16

7 Answers 7

370

You can use the os module.

>>> import os
>>> os.getcwd()
'/home/user'
>>> os.chdir("/tmp/")
>>> os.getcwd()
'/tmp'

But if it's about finding other modules: You can set an environment variable called PYTHONPATH, under Linux would be like

export PYTHONPATH=/path/to/my/library:$PYTHONPATH

Then, the interpreter searches also at this place for imported modules. I guess the name would be the same under Windows, but don't know how to change.

edit

Under Windows:

set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib

(taken from http://docs.python.org/using/windows.html)

edit 2

... and even better: use virtualenv and virtualenv_wrapper, this will allow you to create a development environment where you can add module paths as you like (add2virtualenv) without polluting your installation or "normal" working environment.

http://virtualenvwrapper.readthedocs.org/en/latest/command_ref.html

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5 Comments

Do I have to set PYTHONPATH in the Windows command line or in the Python shell?
@simon ;) astay13: You have to set it in the command line, but I guess there is a graphical menu for making it persistent (otherwise you have to re-set it everytime you reboot or some such, in my case everytime I log in).
@astay13: on Windows you can set it as a global environment variable. Don't have a Windows system to check on right now, but I think you can find it under "Control Panel -> System" -- it's in there somewhere :)
@astray13: You also have the option of ignoring the environment variable and instead appending to sys.path inside of your script.
@astay13: don't set PYTHONPATH globally if you have more than one Python installed (or have programs installed that bundle Python with them -- in other words you'll never know): it may break your installation in mysterious ways
22

you want

import os
os.getcwd()
os.chdir('..')

3 Comments

os.chdir('C:\Users\Ajeya\Documents\') ^ SyntaxError: EOL while scanning string literal
@Whatever, you need to double up backslashes if you use them in a regular (non-raw) Python string. Python also lets you use forward slashes instead. Thus, either os.chdir('C:/Users/Ajeya/Documents'), or os.chdir('C:\\Users\\Ajeya\\Documents'), or os.chdir(r'C:\Users\Ajeya\Documents').
It would be good to note that you call os.getcwd() only for debugging purposes so that we can see what the working directory is before we change it. The code to actually change the cwd is just os.chdir('..')
16
>>> import os
>>> os.system('cd c:\mydir')

In fact, os.system() can execute any command that windows command prompt can execute, not just change dir.

3 Comments

File "<stdin>", line 1 os.system('cd c:\Users\Ajeya\Documents\') ^ SyntaxError: EOL while scanning string literal
@AAI I can’t how this would have worked at all. Windows uses the backslash \ for directories, but in a Python string, as with almost every other language, the backslash is an escape character, which changes the interpretation of the next character. Having \' at the end of the string interprets the final quote as another character, so the string doesn’t get terminated. Having \m should also have caused some sort of error. In Windows, you need to use double backslash \\ for directories to produce a literal backslash character. Go Windows.
That does not work because the system() command changes the cwd only for itself, but not for the parent process. You can check that os.getcwd() will yield the same result before and after any such system() call. Also, to include a backslash \ in a string you have to use \\ or prefix the string with r (for 'raw', viz: r'cd c:\mydir') to avoid that ` \ ` is considered as special (escape) character.
13

The easiest way to change the current working directory in python is using the 'os' package. Below there is an example for windows computer:

# Import the os package
import os

# Confirm the current working directory 
os.getcwd()

# Use '\\' while changing the directory 
os.chdir("C:\\user\\foldername")

1 Comment

use of "\\" and clarification about Windows computer. But I agree the accepted answer is more descriptive.
6

Changing the current directory is not the way to deal with finding modules in Python.

Rather, see the docs for The Module Search Path for how Python finds which module to import.

Here is a relevant bit from Standard Modules section:

The variable sys.path is a list of strings that determines the interpreter’s search path for modules. It is initialized to a default path taken from the environment variable PYTHONPATH, or from a built-in default if PYTHONPATH is not set. You can modify it using standard list operations:

>>> import sys
>>> sys.path.append('/ufs/guido/lib/python')

In answer your original question about getting and setting the current directory:

>>> help(os.getcwd)

getcwd(...)
    getcwd() -> path

    Return a string representing the current working directory.

>>> help(os.chdir)

chdir(...)
    chdir(path)

    Change the current working directory to the specified path.

1 Comment

This answer is gold.. Just add your project directory like this:import sys sys.path.append('/home/g/PycharmProjects/your_project/')
3

If you import os you can use os.getcwd to get the current working directory, and you can use os.chdir to change your directory

Comments

2

You can try this:

import os

current_dir = os.path.dirname(os.path.abspath(__file__))   # Can also use os.getcwd()
print(current_dir)                                         # prints(say)- D:\abc\def\ghi\jkl\mno"
new_dir = os.chdir('..\\..\\..\\')                         
print(new_dir)                                             # prints "D:\abc\def\ghi"


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