Combine multiple csv files by column without pandas

Question

I need to join 4 csv files into one without using pandas based on specific column. I managed to do it with 2 files. But struggle with adding more files to the joined one. the files have columns:

  stoptimes.txt 
  trip_id,departure_time,stop_id 
  stops.txt 
  stop_id,stop_code,stop_name  
  trips.txt
  route_id,trip_id,trip_headsign,vehicle_id  
  vehicles.txt
  vehicle_type_id,vehicle_type_name

desired output is to have all of them in one file I wanted to join stoptimes and stops on stop_id column, then join to this file trip.txt on trip_id column, and then join vehicles file on vehicle_type_id column

stoptimes = []
with open('stop_times.txt', 'r', encoding='utf8') as f:
    for line in f:
        stoptimes.append(line.split(','))

stops = []
with open('stops.txt', 'r', encoding='utf8') as f:
    for line in f:
        stops.append(line.split(','))

trips = []
with open('trips.txt', 'r', encoding='utf8') as f:
    for line in f:
        trips.append(line.split(','))

vehicletypes = []
with open('vehicle_types.txt', encoding='utf8') as f:
    vehicletypes.append(line.split(','))

for (trip_id, arrival_time, departure_time, stop_id, stop_sequence, pickup_type, drop_off_type) in stoptimes:
    for (stop_id, stop_code, stop_name, stop_lat, stop_lon) in stops:
        if stop_id == stop_id:
            print(stop_id, stop_name, trip_id, departure_time)