在python中异常的分析

高洛峰

发布： 2017-03-08 09:49:15

原创

1719人浏览过

每个异常都是一些类的实例，这些实例可以被引发，并且可以用很多种方法进行捕捉，使得程序可以捉住错误并且对其进行处理

>>> 1/0

Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    1/0
ZeroDivisionError: integer division or modulo by zero

登录后复制

异常处理

捕捉异常可以使用try/except语句。

>>> def inputnum():
    x=input('Enter the first number: ')
    y=input('Enter the first number: ')
    try:
        print x/y
    except ZeroDivisionError:
        print "The second number can't be zero"

        
>>> inputnum()
Enter the first number: 10
Enter the first number: 0
The second number can't be zero

登录后复制

raise 触发异常

>>> class Muff:
    muffled=False
    def calc(self,expr):
        try:
            return eval(expr)
        except ZeroDivisionError:
            if self.muffled:
                print 'Division by zero is illegal'
            else:
                raise

            
>>> c=Muff()
>>> c.calc(10/2)

Traceback (most recent call last):
  File "<pyshell#33>", line 1, in <module>
    c.calc(10/2)
  File "<pyshell#31>", line 5, in calc
    return eval(expr)
TypeError: eval() arg 1 must be a string or code object
>>> c.calc('10/2')
>>> c.calc('1/0')

Traceback (most recent call last):
  File "<pyshell#35>", line 1, in <module>
    c.calc('1/0')
  File "<pyshell#31>", line 5, in calc
    return eval(expr)
  File "<string>", line 1, in <module>
ZeroDivisionError: integer division or modulo by zero
>>> c.muffled=True
>>> c.calc('1/0')
Division by zero is illegal

登录后复制

多种异常类型

立即学习“Python免费学习笔记（深入）”；

百度文心百中

百度大模型语义搜索体验中心

查看详情

try:
    x=input('Enter the first number:')
    y=input('Enter the seconed number:')
    print x/y
except ZeroDivisionError:
    print "The second number can't be zero!"
except TypeError:
    print "That wasn't a number,was it?"

登录后复制

同时捕捉多个异常

try:
    x=input('Enter the first number:')
    y=input('Enter the seconed number:')
    print x/y
except(ZeroDivisionError,TypeError,NameError):
    print 'Your numbers were bogus...'

登录后复制

捕捉对象

try:
    x=input('Enter the first number:')
    y=input('Enter the seconed number:')
    print x/y
except(ZeroDivisionError,TypeError),e:
    print e

    
Enter the first number:1
Enter the seconed number:0
integer division or modulo by zero

登录后复制

捕捉所有异常

try:
    x=input('Enter the first number:')
    y=input('Enter the seconed number:')
    print x/y
except:
    print 'something wrong happened...'

    
Enter the first number:
something wrong happened...

登录后复制

更多在python中异常的分析相关文章请关注PHP中文网！