5 Best Ways to Display All Directories Within a Directory in Python

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💡 Problem Formulation: You need to list all directories contained within a given directory. This can be essential for organizing files, managing projects, or scripting maintenance tasks. For instance, given the directory /home/user/projects, you want to see all subdirectories such as /scripts, /images, and /docs that it contains.

Method 1: Using os.listdir() and os.path.isdir()

This method involves using the os module which provides a portable way of using operating system dependent functionality. The os.listdir() function returns a list containing the names of the entries in the directory given by path and os.path.isdir() helps in filtering out directories from files.

Here’s an example:

import os

def list_directories(path):
    return [d for d in os.listdir(path) if os.path.isdir(os.path.join(path, d))]

print(list_directories('/home/user/projects'))

Output:

['scripts', 'images', 'docs']

This code snippet defines a function list_directories() that, when given a path, will return a list of all subdirectories. This is accomplished by iterating through each item in the directory, checking if it’s a directory using os.path.isdir(), and adding it to the list if it is.

Method 2: Using os.scandir()

With Python 3.5 and above, os.scandir() can be used to efficiently list directories. It returns an iterator of os.DirEntry objects corresponding to the entries in the directory given by path. Since it’s more efficient than os.listdir(), it’s preferred for larger directories.

Here’s an example:

import os

def list_directories(path):
    return [entry.name for entry in os.scandir(path) if entry.is_dir()]

print(list_directories('/home/user/projects'))

Output:

['scripts', 'images', 'docs']

In this code snippet, list_directories() performs similarly to the previous example, but uses the os.scandir() function which can be more performance-friendly for the operating system, especially with large directories.

Method 3: Using pathlib.Path()

The pathlib module, introduced in Python 3.4, simplifies path manipulations. By using the Path object’s iterdir() method we can easily iterate over the entries in a directory, and the is_dir() attribute will tell if the entry is a directory.

Here’s an example:

from pathlib import Path

def list_directories(path):
    return [d.name for d in Path(path).iterdir() if d.is_dir()]

print(list_directories('/home/user/projects'))

Output:

['scripts', 'images', 'docs']

This code uses the Path object from the pathlib module for intuitive path handling. The iterdir() method is used to list all entries in the directory and is combined with is_dir() to select only directories.

Method 4: Using glob.glob() with Wildcards

The glob module provides a function glob() that finds all the pathnames matching a specified pattern. By using the wildcard '*/', we can specify that we only want to match directories.

Here’s an example:

import glob

def list_directories(path):
    return glob.glob(f"{path}*/")

print(list_directories('/home/user/projects'))

Output:

['/home/user/projects/scripts/', '/home/user/projects/images/', '/home/user/projects/docs/']

Here, the function list_directories() uses glob.glob() to return all directory paths that match the '*/' pattern. Note that they’re returned with the trailing slash, denoting directories.

Bonus One-Liner Method 5: List Comprehension with pathlib

If you’re a fan of one-liners, here’s a succinct way to list directories using pathlib and list comprehension without defining a function.

Here’s an example:

from pathlib import Path

print([d.name for d in Path('/home/user/projects').iterdir() if d.is_dir()])

Output:

['scripts', 'images', 'docs']

This single line of code achieves the same as the earlier pathlib example without wrapping it in a function. It’s concise but less readable for those not familiar with list comprehensions or pathlib.

Summary/Discussion

  • Method 1: Using os.listdir() and os.path.isdir(). Strengths: Built into Python, straightforward. Weaknesses: Not the most efficient for large directories.
  • Method 2: Using os.scandir(). Strengths: More efficient directory scanning. Weaknesses: Only available in Python 3.5 and above.
  • Method 3: Using pathlib.Path(). Strengths: Intuitive path handling, object-oriented interface. Weaknesses: May be unfamiliar to those used to older Python versions.
  • Method 4: Using glob.glob() with Wildcards. Strengths: Can be used with patterns, easy to use. Weaknesses: Returns full paths which might be unnecessary.
  • Method 5: List Comprehension with pathlib. Strengths: Concise one-liner. Weaknesses: Less readable for novices.