The isdir() function in the path sub-module of the os module is used to determine if a given path is an existing directory or not.

A directory is a container in computer memory that holds files and other directories in a hierarchical structure.

To use the function, we first need to import it in our program as follows.

from os.path import isdir
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Syntax: 
isdir(p)
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p A string representing the path to be checked.

The function checks whether path p represents an existing directory. The path can be relative to the working directory or it can be an absolute path.

Note that the input path:

  • Can be an existing directory path, the function will return True.
  • Can be an existing path but not a directory , False will be returned.
  • Can be invalid and non-existent, False will be returned
from os.path import isdir

paths = ['project/', 'project/tests.py', 'project/images', 'project/images/person.jpg']
for p in paths:
    print(isdir(p))
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Output:
True
False
True
False 

In the above example we used the isdir() function to test whether some pathnames represents existing directories. Of course, the pathnames are only relevant to the computer they were tested on.