Find All Files with Extension in Directory Python - Simple Guide

Use the glob module or os module in Python to find all files with a specific extension in a directory. For example, glob.glob('path/*.txt') lists all text files in the given directory.

Syntax

There are two common ways to find files with a specific extension in Python:

• Using glob: glob.glob('directory_path/*.ext') returns a list of file paths matching the extension.
• Using os and os.path: Loop through files in a directory and check if their names end with the extension using str.endswith().

python

import glob

# Using glob to find all .txt files
files = glob.glob('path/to/directory/*.txt')

# Using os to find all .txt files
import os
files = [f for f in os.listdir('path/to/directory') if f.endswith('.txt')]

Example

This example shows how to find all .py files in the current directory using glob and print their names.

python

import glob

# Find all Python files in current directory
python_files = glob.glob('*.py')

for file in python_files:
    print(file)

Output

example.py
script.py
main.py

Common Pitfalls

Common mistakes when finding files by extension include:

• Not specifying the correct path, leading to empty results.
• Forgetting the dot in the extension (e.g., using 'txt' instead of '.txt').
• Using os.listdir() without filtering for files only, which may include directories.
• Not handling case sensitivity on some systems (e.g., .TXT vs .txt).

python

import os

# Wrong: missing dot in extension
files_wrong = [f for f in os.listdir('.') if f.endswith('txt')]  # misses files ending with '.txt'

# Right: include dot
files_right = [f for f in os.listdir('.') if f.endswith('.txt')]

Quick Reference

Summary tips for finding files with extension:

• Use glob.glob('path/*.ext') for simple pattern matching.
• Use os.listdir() with str.endswith() for manual filtering.
• Always include the dot in the extension (e.g., '.txt').
• Check if you want full paths (glob) or just file names (os.listdir).

Key Takeaways

Use the glob module for easy file extension matching with patterns.

Always include the dot when specifying file extensions (e.g., '.txt').

os.listdir() requires manual filtering with str.endswith() to find files by extension.

Be aware of case sensitivity depending on your operating system.

Check your directory path carefully to avoid empty results.