單例模式

class single_instance(object):
    __instance=None
    def __init__(self):
        pass

    def __new__(cls, *args, **kwargs):
        if cls.__instance==None:
            cls.__instance=object.__new__(cls,*args,**kwargs)
        return cls.__instance

a=single_instance()
b=single_instance()
print(a)
print(b)
輸出結果如下：
<__main__.singleton object at 0x0000016D5191D320>
<__main__.singleton object at 0x0000016D5191D320>