from FCC_database.file_read_backwards import FileReadBackwards

with FileReadBackwards("FCC_database/EN.dat",encoding="utf-8") as in_file, open("calldata.txt", 'w') as out_file:
    callsign_set = set()
    for line in in_file:
        line_list = line.split('|')
        if line_list[4] in callsign_set:
            continue
        else:
            callsign_set.add(line_list[4])
            out_file.write(line_list[4] + "," + line_list[7] + "," + line_list[15] + "," + line_list[16] + "," + line_list[17] + "," + line_list[18] + "\n")