Python – How to Open a File by Regular Expression?

In Python, you can use the glob module’s glob.glob(pattern) function to find all the pathnames matching a specified pattern (e.g., '*.py') according to the rules used by the Unix shell, which includes functionality for wildcard matching that can be used similarly to regular expressions for filename matching.

Here’s a minimal example that filters out all Python files from my Desktop *.py:

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import glob

# Find all .txt files in the current directory
for filename in glob.glob('*.py'):
    with open(filename, 'r') as file:
        content = file.read()
        print(f'Content of {filename}:')
        print(content)

If you need more advanced pattern matching, you can use the re module along with os.listdir() or os.scandir() to filter filenames using regular expressions.

Here’s a minimal example of a file that reads itself:

import re
import os

# Regular expression pattern to match filenames
pattern = re.compile(r'co.*\.py')

# List all files in the current directory
for filename in os.listdir('.'):
    if pattern.match(filename):
        with open(filename, 'r') as file:
            content = file.read()
            print(f'Content of {filename}:')
            print(content)

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