Simple script to extract email addresses from a text file

extract_emails.py

# This script will extract email addresses from a text file
# and print them to the screen; please repurpose this script
# as you see fit.

import re  # Import regular expression module


def open_text_file(file_name):
    '''Open a text file and return a file handle'''
    try:
        file_handle = open(file_name, 'r')
        return file_handle
    except FileNotFoundError:  # If the file does not exist
        print(f"Error: {file_name} not found")
        return None
    except PermissionError:  # File is open
        print("Error: Permission denied, please check file permissions and ensure the file is not open")
        return None
    except OSError:  # Catch all other OS errors
        print("Error: OS Error {OSError}")
        return None
    except Exception as err:
        print(f"Unexpected error: {err}")
        return None


def filter_email_addresses(file_handle):
    '''Filter email addresses from a file handle'''
    email_list = []
    email_regex = re.compile(r'[\w\.-]+@[\w\.-]+')
    for line in file_handle:
        for match in re.finditer(email_regex, line):
            email_list.append(match.group())
    return email_list


def prompt_for_file_name():
    '''Prompt for a file name ending with .txt'''
    file_name = str(
        input("Enter a file name ending with .txt to extract email addresses: "))
    # Check if the file name ends with .txt
    while not file_name.endswith('.txt'):
        # If not, prompt again
        file_name = str(input("Enter a file name ending with .txt: "))
    return file_name


def print_email_addresses(email_list):
    '''Print email addresses from a list'''
    for email in email_list:  # Print each individual email address
        print(email)


def main():
    file_name = prompt_for_file_name()
    file_handle = open_text_file(file_name)
    email_list = filter_email_addresses(file_handle)
    if file_handle:
        file_handle.close()  # Close the file handle; let's be nice to our memory
    if len(email_list) > 0:
        print_email_addresses(email_list)
    else:
        print("No email addresses found")


if __name__ == '__main__':
    main()