Python单例模式

# -*- coding: utf-8 -*-
"""
Created on Sat Dec  8 17:32:05 2018
单例模式
@author: zhen
"""
"""
    普通类
"""
class Man(object):
    def __new__(cls, name):
        return object.__new__(cls)
        
    def __init__(self, name):
        self.name = name
       
"""
    单例类
"""
class Singleton_Pattern_Man(object):
    __man = None  # 私有属性，只能类内直接访问
    __flag = None
    def __new__(cls, name):
        if cls.__man == None:
            cls.__man = object.__new__(cls)
            return cls.__man
        else:
            return cls.__man  # 上一次创建的对象
        
    def __init__(self, name):
        if Singleton_Pattern_Man.__flag == None: # name属性只赋值一次，防止出现歧义
            self.name = name
            Singleton_Pattern_Man.__flag = 1
        
man = Man("吴京")
another_man = Man("杰克")
print(id(man), man.name)
print(id(another_man), another_man.name)
print("----------------------------------")
singleton_man = Singleton_Pattern_Man("吴京")
singleton_another_man = Singleton_Pattern_Man("杰克")
print(id(singleton_man), singleton_man.name)
print(id(singleton_another_man), singleton_another_man.name)
# print(Singleton_Pattern_Man.__man) # 私有属性不能直接访问

结果：