Python中type的构造函数参数含义说明88bf必发

测试代码如下:

Python中type的构造函数参数含义说明,python构造函数

测试代码如下:
复制代码 代码如下:
 class ModelMetaClass(type):
     def __new__(cls,name,base,attrs):
         logging.info(“cls is:”+str(cls))
         logging.info(“name is:”+str(name))
         logging.info(“base is:”+str(base))
         logging.info(“attrs is:”+str(attrs))
         return type.__new__(cls,name,base,attrs)
         pass
     pass
 
 class Model(dict):
     __metaclass__ = ModelMetaClass
     def __init__(self):
         pass
     pass
 
 def main():
     m=Model()
 
 if __name__ == ‘__main__’:
     main()

测试结果:
复制代码 代码如下:
 INFO:root:cls is:<class ‘__main__.ModelMetaClass’>
 INFO:root:name is:Model
 INFO:root:base is:(<type ‘dict’>,)
 INFO:root:attrs is:{‘__module__’: ‘__main__’,
‘__metaclass__’: <class ‘__main__.ModelMetaClass’>,
‘__init__’: <function __init__ at 0x025C76F0>}

结论就显而易见了。cls是当前类的名字,即类本身。name是通过__metaclass__属性指向ModelMetaClass的类,即要实例化的类,ModelMetaClass拦截了该类的实例化。base是要实例化的类的基类。attrs是要实例化的类的属性集合。

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测试代码如下: 复制代码 代码如下: class ModelMetaClass(type): def
__new__(cls,name,base,attrs): l…

复制代码 代码如下:

 class ModelMetaClass(type):
     def __new__(cls,name,base,attrs):
         logging.info(“cls is:”+str(cls))
         logging.info(“name is:”+str(name))
         logging.info(“base is:”+str(base))
         logging.info(“attrs is:”+str(attrs))
         return type.__new__(cls,name,base,attrs)
         pass
     pass
 
 class Model(dict):
     __metaclass__ = ModelMetaClass
     def __init__(self):
         pass
     pass
 
 def main():
     m=Model()
 
 if __name__ == ‘__main__’:
     main()

测试结果:

复制代码 代码如下:

 INFO:root:cls is:<class ‘__main__.ModelMetaClass’>
 INFO:root:name is:Model
 INFO:root:base is:(<type ‘dict’>,)
88bf必发, INFO:root:attrs is:{‘__module__’: ‘__main__’,
‘__metaclass__’: <class ‘__main__.ModelMetaClass’>,
‘__init__’: <function __init__ at 0x025C76F0>}

结论就显而易见了。cls是当前类的名字,即类本身。name是通过__metaclass__属性指向ModelMetaClass的类,即要实例化的类,ModelMetaClass拦截了该类的实例化。base是要实例化的类的基类。attrs是要实例化的类的属性集合。

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