Get CAN IDs present only in the second file, log also the number of their occurances

unique-ids-from-second-file.py

import sys
import collections


def extract_ids(filename):
    with open(filename, "r") as file:
        return [line.split()[2].split("#")[0] for line in file]


def count_ids(filename):
    with open(filename, "r") as file:
        return collections.Counter(line.split()[2].split("#")[0] for line in file)


if len(sys.argv) == 3:
    # Files should be CAN log files recorded with the `candump` CLI.
    
    file_without_command_ids = set(extract_ids(sys.argv[1]))
    file_with_command_id_counts = count_ids(sys.argv[2])

    for id, count in file_with_command_id_counts.items():
        if id not in file_without_command_ids:
            print(
                f"ID {id} is present only in the second file and occurs {count} times."
            )
else:
    print("Please provide two file names as arguments.")