Exception analysis in python

Each exception is an instance of some classes. these instances can be thrown and can be captured in many ways, this allows the program to catch errors and process them. Each exception is a type of instance. these instances can be thrown and can be captured in many ways, this allows the program to catch and process errors.

>>> 1/0Traceback (most recent call last):  File "
 
  ", line 1, in 
  
       1/0ZeroDivisionError: integer pision or modulo by zero
  
 

Exception handling

You can use the try/try T statement to catch exceptions.

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

Raise trigger exception

>>> 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 "
 
  ", line 1, in 
  
       c.calc(10/2)  File "
   
    ", 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 "
    
     ", line 1, in 
     
          c.calc('1/0')  File "
      
       ", line 5, in calc return eval(expr) File "
       
        ", line 1, in 
        
         ZeroDivisionError: integer pision or modulo by zero>>> c.muffled=True>>> c.calc('1/0')Division by zero is illegal
        
       
      
     
    
   
  
 

Multiple Exception types

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

Capture multiple exceptions at the same time

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

Object capturing

try:    x=input('Enter the first number:')    y=input('Enter the seconed number:')    print x/yexcept(ZeroDivisionError,TypeError),e:    print e    Enter the first number:1Enter the seconed number:0integer pision or modulo by zero

Catch all exceptions

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

For more articles about exception analysis in python, refer to PHP Chinese network!