How to find if directory exists in Python

Python 3.4 introduced the pathlib module into the standard library, which provides an object oriented approach to handle filesystem paths. The is_dir() and exists() methods of a Path object can be used to answer the question:

In [1]: from pathlib import Path

In [2]: p = Path('/usr')

In [3]: p.exists()
Out[3]: True

In [4]: p.is_dir()
Out[4]: True

Paths (and strings) can be joined together with the / operator:

In [5]: q = p / 'bin' / 'vim'

In [6]: q
Out[6]: PosixPath('/usr/bin/vim') 

In [7]: q.exists()
Out[7]: True

In [8]: q.is_dir()
Out[8]: False

Pathlib is also available on Python 2.7 via the pathlib2 module on PyPi.

Use os.path.isdir for directories only:

>>> import os
>>> os.path.isdir('new_folder')
True

Use os.path.exists for both files and directories:

>>> import os
>>> os.path.exists(os.path.join(os.getcwd(), 'new_folder', 'file.txt'))
False

Alternatively, you can use pathlib:

 >>> from pathlib import Path
 >>> Path('new_folder').is_dir()
 True
 >>> (Path.cwd() / 'new_folder' / 'file.txt').exists()
 False