python内置方法、模块讲解（十六）

• 2016-03-15 22:08:39
• 1489
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• python
• authen

四十三、isinstance方法

1、定义：

isinstance(...)
    isinstance(object, class-or-type-or-tuple) -> bool

    Return whether an object is an instance of a class or of a subclass thereof.    With a type as second argument, return whether that is the object's type.
    The form using a tuple, isinstance(x, (A, B, ...)), is a shortcut for
    isinstance(x, A) or isinstance(x, B) or ... (etc.).

2、解释：返回bool类型。用来判断一个对象是否是一个类的实例或者子类的实例，或者判断是否为某种对象类型。

3、举例：

>>> isinstance('aa',basestring)
True
>>> isinstance(u'aa',basestring)
True
>>> isinstance(1,(basestring,int))
True
>>> isinstance('aa',str)
True
>>> isinstance(u'aa',str)
False

四十四、issubclass方法

1、定义：

issubclass(...)
    issubclass(C, B) -> bool

    Return whether class C is a subclass (i.e., a derived class) of class B.
    When using a tuple as the second argument issubclass(X, (A, B, ...)),
    is a shortcut for issubclass(X, A) or issubclass(X, B) or ... (etc.).

2、解释：从名字可以看出，此方法与上面的isinstance作用相似：即用来判断一个类是否是一个类的子类或者继承类。

3、举例：

>>> issubclass(str, unicode)
False
>>> issubclass(str, basestring)
True
>>> issubclass(str, (unicode,basestring))
True