[Python基础]008.异常

异常

异常处理
一些常见的异常

异常处理

捕获异常

try/except 与C,java等语言用try/catch来捕获异常相似，Python使用try/except
try/except/finally 无论是否有异常都会执行finally下的语句
try/except/else 没有抛出异常时执行else下的语句

代码

try:

    f = open('data.txt')

    f.read()

    print zz

    print 5/0

except IOError, e:              # 捕获IO异常，变量e接收具体的错误信息

    print e

except NameError, e:            # 捕获名字异常

    print e

except Exception, e:            # 捕获剩下的其他异常

    print e

else:                           # 没有异常时执行

    print 'no error'            

finally:                        # 无论有无异常都会执行的内容

    print 'do anyway'

抛出异常

raise 抛出一个异常

代码

def error_fun():

    raise Exception('it is an error function')  # 抛出一个通用异常Exception

# 捕获上面的异常

try:

    error_fun()

execept Exception, e:

    print e

自定义异常

通过继承异常类，就可以自定义异常。最常见的就是直接继承自Exception类。

# 自定义异常

class MyException(Exception):

    def __init__(self, arg, arg2):

        Exception.__init__(self, arg)

        self.arg2 = arg2

# 捕获

try:

    raise MyException('abc', 10)

except MyException, e:

    print e, e.arg2

一些常见的异常

Exception 基础异常
ZeroDivisionError 除数为0异常
OverflowError 内存溢出
ImportError 导入模块异常
NameError 没有声明对象
RuntimeError 一般运行时异常
NotImplementedError 未实现方法
SyntaxError 语法错误
IOError IO操作异常
...

本站文章为宝宝巴士 SD.Team原创，转载务必在明显处注明：（作者官方网站：宝宝巴士)
转载自【宝宝巴士SuperDo团队】 原文链接: http://www.cnblogs.com/superdo/p/4581764.html

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