创建同时是实例方法和类方法的方法
在Python中,我希望能够创建一个既充当类函数又充当实例方法的函数,但能够更改行为。其用例是一组可序列化的对象和类型。举个例子:
>>> class Thing(object):
#...
>>> Thing.to_json()
'A'
>>> Thing().to_json()
'B'
我知道,鉴于 Python 源代码中 funcobject.c 中 classmethod() 的定义,使用 C 模块看起来会很简单。有没有办法从 python 中做到这一点?
谢谢!
通过描述符的提示,我能够使用以下代码来完成此操作:
class combomethod(object):
def __init__(self, method):
self.method = method
def __get__(self, obj=None, objtype=None):
@functools.wraps(self.method)
def _wrapper(*args, **kwargs):
if obj is not None:
return self.method(obj, *args, **kwargs)
else:
return self.method(objtype, *args, **kwargs)
return _wrapper
谢谢亚历克斯!
In Python, I'd like to be able to create a function that behaves both as a class function and an instance method, but with the ability to change behaviors. The use case for this is for a set of serializable objects and types. As an example:
>>> class Thing(object):
#...
>>> Thing.to_json()
'A'
>>> Thing().to_json()
'B'
I know that given the definition of classmethod() in funcobject.c in the Python source, this looks like it'd be simple with a C module. Is there a way to do this from within python?
Thanks!
With the hint of descriptors, I was able to do it with the following code:
class combomethod(object):
def __init__(self, method):
self.method = method
def __get__(self, obj=None, objtype=None):
@functools.wraps(self.method)
def _wrapper(*args, **kwargs):
if obj is not None:
return self.method(obj, *args, **kwargs)
else:
return self.method(objtype, *args, **kwargs)
return _wrapper
Thank you Alex!
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当然,您只需要定义自己的描述符类型。 这里有一个关于 Python 描述符的优秀教程。
Sure, you just need to define your own descriptor type. There's an excellent tutorial on Python descriptors here.