在Python中为命令行上的错误用户ID创建异常

Question

The user needs to enter a path to their file along with an id that is on every line in their file. I have created an exception for a wrong file and I want to do the same if the id that is typed doesn't match what's in the file. How do I do this?

import ConfigParser, os
import csv
import sys, getopt
import time
import datetime

from sys import argv
script, solutionId, input_file = argv

def check_all(f):
    print f.read()

def print_a_line(line_count, f):
    print line_count, f.readline()

try:
    current_file = open(input_file)
    check_all(current_file)
except IOError, e:
    print '%s, please try again.' % e

Answer 1

Well just declare your exception:

class WrongId(Exception): pass

And raise it when checking the file integrity:

if not check_id_in_file(input_id):
    raise WrongId()