本文实例讲述了Python编程中属性和方法使用技巧。分享给大家供大家参考。具体分析如下:
一、属性
在python中,属性分为公有属性和私有属性,公有属性可以在类的外部调用,私有属性不能在类的外部调用。公有属性可以是任意变量,私有属性是以双下划线开头的变量。
下面我们定义一个People类,它有一个公有属性name,和一个私有属性__age。
class People(): def __init(self): self.name='张珊' self.__age=24
我们创建一个People类的实例,P1,当我们调用它的私有属性__age时发现有如下错误。
>>> p1.__age
Traceback (most recent call last):
File "
p1.__age
AttributeError: 'People' object has no attribute '__age'
这就说明了私有属性不可以在类的外部使用。那么我们要想调用私有属性的值,就可以在类的内部通过定义一个方法来调用。
>>> class People(): def __init__(self): self.name='jack' self.__age=23 def showinfo(self): print(self.__age) >>> p2=People() >>> p2.showinfo() 23
可能有人会问,为什么加上双下划线的属性,我们就不可以在类的外部调用了呢?那么下面我们就探讨下python面向对象的私有机制。
Python中以双下划线开头的属性和方法,在被实例化后会自动在其名字前加_classname.因为名字被改变了,所以自然无法通过双下滑线开头的名字来访问,从而达到不可进入的目的。
我们可以通过实例名.__dict__来查看对象的属性集合。
Python中不同于其他面向对象的编程语言,python的设计哲学就是简单至上,因此如果你真的想要调用私有属性的话还是可以调用的。
二、方法
在python中方法分为公有方法、私有方法、类方法和静态方法。
下面我们看一个比较完整的例子
#!/usr/bin/python #coding:utf-8 __author__ = 'MXi4oyu' class People(): def __init__(self): self.name='张珊' self.__age=23 def fun1(self): #共有方法可以在类的外部进行调用 #可以通过对象名.方法名来调用 print("共有方法") def __fun2(self): #私有方法不能在类的外部进行调用 #可以在类的其他方法中调用私有方法 print("私有方法") def funcshow(self): self.__fun2() @classmethod #类方法要加上@classmethod修饰器,类方法可以通过类名.方法名进行调用 def fun3(self): print("类方法") @staticmethod #静态方法需要加上@staticmethod修饰器,静态方法不需要加self, #同样可以通过类名.方法名调用 def fun4(): print("静态方法") if __name__=='__main__': p1=People() p1.fun1() p1.funcshow() People.fun3() People.fun4()
希望本文所述对大家的Python程序设计有所帮助。

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