python异常处理示例代码

#!/usr/bin/env python# -*- coding: utf-8 -*-import systry:    f = open('myfile.txt')    s = f.readline()    i = int(s.strip())except IOError as (errno, strerror):    print "I/O error({0}): {1}".format(errno, strerror)except ValueError:    print "Could not convert data to an integer."except:    print "Unexpected error:", sys.exc_info()[0]    raiseelse:    print "I will always go here if there is no except!"#自定义异常处理class MyError(Exception):    def __init__(self, value):        self.value = value            def __str__(self):        return repr(self.value)        try:    raise MyError(2*2)except MyError as e:    print "My exception occured, value: ", e.value    #raise MyError('oops!')# try - except - else - finallydef divide(x, y):    try:        result = x / y    except ZeroDivisionError:        print "Divide by zero"    else:        print "The result is ", result    finally:        print "executing finally clause"        divide(2, 1)divide(2, 0)