python-kurs-softed/beispiele/readfile3.py

#!/usr/bin/env python

import sys

filename = sys.argv[1]

with open(filename, "r") as fileobj:
    max_linelength = 0
    longest_line = -1

    for i, line in enumerate(fileobj):
        if len(line) > max_linelength:
            max_linelength = len(line)
            longest_line = i + 1

print(f"The longest line is line {longest_line} with a length of {max_linelength}.")