Get the file names within a directory which match specified pattern

count_fles_pattern.py

import os
import re
import sys
from typing import List

class FileSystem:
    def __init__(self, path='.') -> None:
        self.path = path

    def filter_files(self, files, pattern) -> List[str]:
        regex = re.compile(pattern)
        return [f for f in files if regex.search(f)]

    def files(self) -> List[str]:
        try:
            all_files: List[str] = []
            for dirpath, _, filenames in os.walk(self.path):
                for filename in filenames:
                    full_path = os.path.join(dirpath, filename)
                    full_path = full_path.replace('\\', '/')
                    all_files.append(full_path)
            return all_files
        except OSError as e:
            print(f"Error: Unable to access directory '{self.path}': {e}")
            return []

    def count(self) -> int:
        return len(self.files())

    def regex_files(self, pattern: str) -> List[str]:
        pattern = re.sub(r'[^a-zA-Z0-9]', '', pattern)
        regex = re.compile(pattern)
        return [f for f in self.files() if regex.match(f)]

    def __str__(self) -> str:
        return f'FileSystem({self.path})'

def main() -> None:
    fs = FileSystem()
    print(f'Files in {fs}: {fs.count()}')

    if len(sys.argv) > 1:
        pattern = sys.argv[1]
        print(f'Files matching pattern "{pattern}": {fs.regex_files(pattern)}')

if __name__ == '__main__':
    main()