python中isinstance函数判断各种类型的小细节

Return true if the object argument is an instance of the classinfo argument, or of a (direct, indirect or virtual)

subclass thereof. Also return true if classinfo is a type object (new-style class) and object is an object of that

type or of a (direct, indirect or virtual) subclass thereof. If object is not a class instance or an object of the

 given type, the function always returns false. If classinfo is neither a class object nor a type object, it may be a

 tuple of class or type objects, or may recursively contain other such tuples (other sequence types are not accepted).

 If classinfo is not a class, type, or tuple of classes, types, and such tuples, a TypeError exception is raised.

>>> isinstance(u'3.0', unicode)

True

>>> isinstance('3.0', str)

True

>>> isinstance(u'3.0', str)

False

>>> isinstance(u'3.0', str)

False

>>> isinstance(u'3.0', basestring)

True

>>> isinstance('3.0', basestring)

True

>>> isinstance('3', (int, float))

False

>>> isinstance(3.0, (int, float))

True

>>> isinstance(3, (int, float))

True

>>> isinstance(3.0, float)

True

>>> isinstance(3.0, int)

False

>>> isinstance(3, float)

False

>>> isinstance(3, int)

True