regex for filter string code example

Example: Filter regex

import os
import re
 
def find_files(file_type):
    os.chdir(path)
    with os.scandir(path) as it:
        for entry in it:
            if entry.name.endswith(file_type) and entry.is_file():
                yield entry.name
 
def find_in_file(files, pattern):
    for file in files:
        with open(file, encoding='utf-8') as f:
            for index, line in enumerate(f, 1):
                for match in re.finditer(pattern, line):
                    print(f'Found <{line.strip()}> in file <{file}> on line <{index}>')
 
if __name__ == '__main__':
    path = r'E:\div_code\new\cat_pic'
    pattern = re.compile(r'cat|dog\d\d(?!\d)')
    file_type = '.txt'
    files = find_files(file_type)
    find_in_file(files, pattern)