标签:允许 mat sel 时机 block get setattr 自己 python面向对
Python并不直接支持私有方式,而要靠程序员自己把握在外部进行特性修改的时机。
为了让方法或者特性变为私有(从外部无法访问),只要在它的名字前面加上双下划线即可。
由双下划线
__
开始的属性在运行时被“混淆”,所以直接访问是不允许的。实际上,在 Python 带有双下划线的属性或方法并非正真意义上的私有,它们仍然可以被访问。
在类的内部定义中,所有以双下划线开始的名字都被“翻译”成前面加上单下划线和类名的形式。
>>> class TestObj(object): ... __war = "world" ... ... def __init__(self): ... self.__har = "hello" ... ... def __foo(self): ... print(self.__har + self.__war) ... ... ... >>> t = TestObj() >>> dir(t) # 拿到t里面的所有方法 [‘_TestObj__foo‘, ‘_TestObj__har‘, ‘_TestObj__war‘, ‘__class__‘, ‘__delattr__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getat tribute__‘, ‘__gt__‘, ‘__hash__‘, ‘__init__‘, ‘__le__‘, ‘__lt__‘, ‘__module__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__setattr__ ‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘] >>> t.__war Traceback (most recent call last): File "<input>", line 1, in <module> t.__war AttributeError: ‘TestObj‘ object has no attribute ‘__war‘ >>> t.__har Traceback (most recent call last): File "<input>", line 1, in <module> t.__har AttributeError: ‘TestObj‘ object has no attribute ‘__har‘ >>> t.foo() Traceback (most recent call last): File "<input>", line 1, in <module> t.foo() AttributeError: ‘TestObj‘ object has no attribute ‘foo‘ >>> t._TestObj__war ‘world‘ >>> t._TestObj__har ‘hello‘ >>> t._TestObj__foo() helloworld
标签:允许 mat sel 时机 block get setattr 自己 python面向对
原文地址:https://www.cnblogs.com/bigtreei/p/9029528.html