How do I check if a directory exists in Python?

To check if a directory exists in Python, you can use either the os module or the pathlib module (Python 3.4+). Here’s how to do it:

Method 1: Using os.path.isdir

import os

directory_path = "/path/to/directory"

if os.path.isdir(directory_path):
    print(f"The directory '{directory_path}' exists.")
else:
    print(f"The directory '{directory_path}' does not exist.")

Key Notes:

• Behavior: Returns True if the path exists and is a directory.
• Handles: Symbolic links (returns True if the link points to a directory).
• Case Sensitivity: Matches the OS (case-sensitive on Linux/macOS, case-insensitive on Windows).

Method 2: Using pathlib (Modern/OOP Approach)

from pathlib import Path

directory_path = Path("/path/to/directory")

if directory_path.is_dir():
    print(f"The directory '{directory_path}' exists.")
else:
    print(f"The directory '{directory_path}' does not exist.")

Key Notes:

• Object-Oriented: Uses Path objects for cleaner code.
• Same Behavior: Like os.path.isdir, it checks both existence and directory type.

Edge Cases

1. Check if a Path Exists (File or Directory):

   os.path.exists("/path/to/item")  # True if file/directory exists

2. Check if a Path is a File:

   os.path.isfile("/path/to/file")  # True if path is a file

3. Symbolic Links:

• os.path.isdir and Path.is_dir() follow symbolic links by default.
• To check if a path is a symbolic link itself (not its target), use:
  python os.path.islink("/path/to/symlink") # True if path is a symlink

Example Workflow

from pathlib import Path

def check_directory(path):
    dir_path = Path(path)
    if dir_path.is_dir():
        print(f"Directory '{dir_path}' exists.")
    else:
        print(f"Directory '{dir_path}' does not exist. Creating it...")
        dir_path.mkdir(parents=True, exist_ok=True)  # Optional: Create the directory

check_directory("./my_folder")

Summary

• Use os.path.isdir for quick checks (traditional approach).
• Use pathlib.Path.is_dir() for modern, readable code.
• Both methods reliably check for directory existence across OS platforms.