Python整理异常处理

 try/except语句一般情况下都是用来捕捉程序无法预知的异常

语法解析

 try:
     [语句]
 except [错误类型] as [别名]:
     [根据当前错误的类型，执行不同的语句]
 except exception as [别名]:
     [其他未知的错误可以通过exception来捕捉]
 else:
     [没有发生错误执行的语句]
 finally:
     [退出try时必须执行的语句]

 #!/usr/bin/env python3
 # -*- coding:utf-8 -*-
 try:
     a = open("test.txt", 'r')
 except Exception as e:
     print(e)
     with open("test.txt",'w') as a:
         a.write("written!")
     with open("test.txt",'r') as a:
         print(a.read())
 ''' 
 output:
 [Errno 2] No such file or directory: 'test.txt'
 written!
 '''