python中的Init方法， new 方法 call 方法
new 方法实现单列模式思考 class Single: _single = None _single_only = None def __init__(self, value): self.v = value print(self.v) def __new__(cls, *args, **kwargs): if Single._single: return Single._single else: Single._single = super(Single, cls).__new__(cls, *args, **kwargs) print("只执行一次") return Single._single s2 = Single(2) #结果报错 Single._single = super(Single, cls).__new__(cls, *args, **kwargs) TypeError: object() takes no parameters 报错显示 基类 object() 不接受额外参数 ....... def __new__(cls, *args, **kwargs): if Single._single: return Single._single else: Single._single = super(Single, cls).__new__(cls)