python类参数self使用示例

class Foo(object):
    def __new__(cls, *args, **kwargs):
        """如果不覆盖这个__new__方法,也就是说不写这个__new__方法，类会从object
        继承__new__方法完成返回值实例对象
        """
        print "__new__方法先被调用"
        tmp = super(Foo,cls).__new__(cls,*args, **kwargs)
        print id(tmp)
        print type(tmp)
        print isinstance(tmp,Foo)
        print issubclass(type(tmp),Foo)
        return tmp

    def __init__(self):
        """self是python默认传的值，该值是调用__new__的返回值"""
        print "__init__被调用"
        print id(self)

p = Foo()
print id(p)
print type(p)