Python Singleton

# __new__ 返回实例时,__init__ 才会被调用
class Singleton(object):
_instance = None
def __new__(cls, *args):
if not isinstance(cls._instance, cls):
cls._instance = super(Singleton, cls).__new__(cls, *args)
return cls._instance

def __init__(self, name):
self.name = name

if __name__ == '__main__':
# 创建Singleton两个引用,指向同一个对象,
# 证明:
#   使用不同的初始化参数,初始化不同引用指向的对象,
#   然后打印两个不同引用指向的对象的数据域,结果相同
s1 = Singleton("Google")
s2 = Singleton("Versign")
print(s1.name)
print(s2.name)
print(id(s1) == id(s2))