Python运算符重载用法实例分析
本文实例讲述了Python运算符重载用法。分享给大家供大家参考。具体如下：
在Python语言中提供了类似于C++的运算符重在功能：
一下为Python运算符重在调用的方法如下：
Method Overloads Callfor
__init__ 构造函数 X=Class()
__del__ 析构函数 对象销毁
__add__ + X+Y,X+=Y
__or__ | X|Y,X|=Y
__repr__ 打印转换 printX，repr(X)
__str__ 打印转换 printX，str(X)
__call__ 调用函数 X()
__getattr_ 限制 X.undefine
__setattr__ 取值 X.any=value
__getitem__ 索引 X[key]，
__len__ 长度 len(X)
__cmp__ 比较 X==Y,X<Y
__lt__ 小于 X<Y
__eq__ 等于 X=Y
__radd__ Right-Side+ +X
__iadd__ += X+=Y
__iter__ 迭代 ForIn
1.减法重载
classNumber: def__init__(self,start): self.data=start def__sub__(self,other):#minusmethod returnNumber(self.data-other) number=Number(20) y=number–10#invoke__sub__method classNumber: def__init__(self,start): self.data=start def__sub__(self,other):#minusmethod returnNumber(self.data-other) number=Number(20) y=number–10#invoke__sub__method
2.迭代重载
classindexer: def__getitem__(self,index):#iteroverride returnindex**2 X=indexer() X[2] foriinrange(5): printX[i] classindexer: def__getitem__(self,index):#iteroverride returnindex**2 X=indexer() X[2] foriinrange(5): printX[i]
3.索引重载
classstepper: def__getitem__(self,i): returnself.data[i] X=stepper() X.data='Spam' X[1]#call__getitem__ foriteminX:#call__getitem__ printitem classstepper: def__getitem__(self,i): returnself.data[i] X=stepper() X.data='Spam' X[1]#call__getitem__ foriteminX:#call__getitem__ printitem
4.getAttr/setAttr重载
classempty: def__getattr__(self,attrname): ifattrname=='age': return40 else: raiseAttributeError,attrname X=empty() printX.age#call__getattr__ classaccesscontrol: def__setattr__(self,attr,value): ifattr=='age': #Self.attrname=valueloops! self.__dict__[attr]=value else: printattr raiseAttributeError,attr+'notallowed' X=accesscontrol() X.age=40#call__setattr__ X.name='wang'#raiseexception classempty: def__getattr__(self,attrname): ifattrname=='age': return40 else: raiseAttributeError,attrname X=empty() printX.age#call__getattr__ classaccesscontrol: def__setattr__(self,attr,value): ifattr=='age': #Self.attrname=valueloops! self.__dict__[attr]=value else: printattr raiseAttributeError,attr+'notallowed' X=accesscontrol() X.age=40#call__setattr__ X.name='wang'#raiseexception
5.打印重载
classadder: def__init__(self,value=0): self.data=value def__add__(self,other): self.data+=other classaddrepr(adder): def__repr__(self): return'addrepr(%s)'%self.data x=addrepr(2)#run__init__ x+1#run__add__ printx#run__repr__ classadder: def__init__(self,value=0): self.data=value def__add__(self,other): self.data+=other classaddrepr(adder): def__repr__(self): return'addrepr(%s)'%self.data x=addrepr(2)#run__init__ x+1#run__add__ printx#run__repr__
6.Call调用函数重载
classProd: def__init__(self,value): self.value=value def__call__(self,other): returnself.value*other p=Prod(2)#call__init__ printp(1)#call__call__ printp(2) classProd: def__init__(self,value): self.value=value def__call__(self,other): returnself.value*other p=Prod(2)#call__init__ printp(1)#call__call__ printp(2)
7.析构函数重载
classLife:
def__init__(self,name='name'):
print'Hello',name
self.name=name
def__del__(self):
print'Goodby',self.name
brain=Life('Brain')#call__init__
brain='loretta'#call__del__
希望本文所述对大家的Python程序设计有所帮助。