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python 自定义元类

Python　2024/7/5 21:41:38　　点击：不统计

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定义元类继承type 类。重写两个方法，并且参数固定。
def __new__(cls, name, bases, dct):
def __init__(cls, name, bases, dct):

class MyMeta(type):

registry = {} # 记录所有的对象

def __new__(cls, name, bases, dct): # 重写新建里方法

print(f"Creating class {name}")

new_class = super().__new__(cls, name, bases, dct)

cls.registry[name] = new_class

return super().__new__(cls, name, bases, dct)

def __init__(cls, name, bases, dct): # 重新init

print(f"Initializing class {name}")

super().__init__(name, bases, dct)

@classmethod

def all_obj(cls):

return cls.registry

class MyClass(metaclass=MyMeta):

pass

a = MyClass()

print(a)

print(MyMeta.all_obj())

# 输出结果：

# Creating class MyClass

# Initializing class MyClass

# <__main__.MyClass object at 0x10d103730 >

# {'MyClass': <class '__main__.MyClass'>}

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