python 设计模式

单例---类方法方式

class Single():
    def __init__(self, name): self.name = name  @classmethod def instance(cls, *args, **kwargs): if not hasattr(Single, "_instance"): Single._instance = Single(*args, **kwargs) return Single._instance s1 = Single.instance('Gage') s2 = Single.instance() print(s1) print(s2)

单例---new方式

class Single(object):
    __isstance = None __first_init = False def __new__(cls, *args, **kwargs): if not cls.__isstance: cls.__isstance = object.__new__(cls) return cls.__isstance def __init__(self, name): if not self.__first_init: self.name = name Singleton.__first_init = True a = Single('a') b = Single('b') print(id(a)) print(id(b))

工厂模式

 

# 首先定义一个抽象基类
class CarStore(object): # 定义生产汽车的方法 def createcar(self, name): pass # 根据类型去生产车 def order(self, name): self.car = self.createcar(name) self.car.move() # 定义4s店 实现抽象类 class AoDiCarStore(CarStore): def createcar(self, name): self.factory = CarFactory() return self.factory.createcar(name) # 创建一个车 class AoDi(): def move(self): print('移动') # 定义一个工厂 class CarFactory(): def createcar(self, name): self.name = name if self.name == 'AoDi': self.car = AoDi() return self.car aodi = AoDiCarStore() aodi.order('AoDi')

 

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