In case the folder contains a lot of files or memory is an constraint, consider using generators:
def yield_files_with_extensions(folder_path, file_extension):
for _, _, files in os.walk(folder_path):
for file in files:
if file.endswith(file_extension):
yield file
Option A: Iterate
for f in yield_files_with_extensions('.', '.txt'):
print(f)
Option B: Get all
files = [f for f in yield_files_with_extensions('.', '.txt')]