python面向对象代码示例

古城微笑少年丶 2022-05-25 08:55 185阅读 0赞

### 以python2.7为例说明 ###

【示例一】指定调用哪个类实例的函数

>>> class Foo(object):
            def func(self):
                print "foo's function"
    
    >>> class Bar(Foo):
            def func(self):
                print "bar's function"
    
    >>> obj = Bar()
    >>> # this will call Bar's function
    >>> obj.func()
    bar's function
    >>> obj.__class__ = Foo  # 指定该对象所属的类
    >>> obj.func()
    foo's function
    >>>

【示例二】直接调用类的实例，而不是调用实例的方法

>>> class Hi(object):
            def __init__(self, x, y):
                self.__x = x
                self.__y = y
            def myfunc(self):
                print "x=", self.__x, "b=", self.__y
    
    >>> h = Hi("good", "job")
    >>> h.myfunc()  # 此处调用该实例的方法
    x= good b= job
    >>> h("ok")   # 无法直接调用此类的实例
    ---------------------------------------------------------------------------
    TypeError                                 Traceback (most recent call last)
    <ipython-input-22-d4380afdeffd> in <module>()
    ----> 1 h("ok")
    
    TypeError: 'Hi' object is not callable
    >>> # 如何能直接调用实例？这里有个关键的方法__call__()能实现此类的实例可直接调用
    >>> class Hi(object):
            def __init__(self, x, y):
                self.__x = x
                self.__y = y
            def myfunc(self):
                print "x=", self.__x, "b=", self.__y
            def __call__(self, arg):
                print "call:", arg + self.__x + self.__y
    
    >>> h2 = Hi("nice", "guy")
    >>> h2.myfunc()
    x= nice b= guy
    >>> h2("yeah~")    # __call__ 函数能实现此类的实例可直接调用
    call: yeah~niceguy

好了，就写到这里，看官们觉得涨知识了，请在文章左侧点个赞 \_