python - 为什么 python 2 -> 3 中的 inspect.ismethod 和 inspect.isfunction 之间存在差异？

Question

所以这段代码:

from inspect import *

class X(object):
  def y(self):
    pass

methods = getmembers(X, predicate=ismethod)
functions = getmembers(X, predicate=isfunction)

print("%r" % methods)
print("%r" % functions)

从 python2.7 产生:

[('y', <unbound method X.y>)]
[]

从 python3.3 产生:

[]
[('y', <function X.y at 0x1006ee3b0>)]

我四处搜寻，但我看不出这种行为变化有任何明显的原因。

具体来说，为什么 python 3 将我的方法视为函数？

是否有任何跨运行时的方法来获取类的方法列表？

(即在 python2.X 和 3.X 上运行时返回相同的东西)

编辑:getmembers() 不工作的例子:

from inspect import *

class X(object):
  def y(self):
    pass

methods = getmembers(X)
for i in methods:
  if ismethod(i):
    print("Method: %s" % str(i))
  else:
    print("Not a method: %s" % str(i))

打印:

Not a method: ('__class__', <attribute '__class__' of 'object' objects>)
Not a method: ('__delattr__', <slot wrapper '__delattr__' of 'object' objects>)
Not a method: ('__dict__', <attribute '__dict__' of 'X' objects>)
Not a method: ('__dir__', <method '__dir__' of 'object' objects>)
Not a method: ('__doc__', None)
Not a method: ('__eq__', <slot wrapper '__eq__' of 'object' objects>)
Not a method: ('__format__', <method '__format__' of 'object' objects>)
Not a method: ('__ge__', <slot wrapper '__ge__' of 'object' objects>)
Not a method: ('__getattribute__', <slot wrapper '__getattribute__' of 'object' objects>)
Not a method: ('__gt__', <slot wrapper '__gt__' of 'object' objects>)
Not a method: ('__hash__', <slot wrapper '__hash__' of 'object' objects>)
Not a method: ('__init__', <slot wrapper '__init__' of 'object' objects>)
Not a method: ('__le__', <slot wrapper '__le__' of 'object' objects>)
Not a method: ('__lt__', <slot wrapper '__lt__' of 'object' objects>)
Not a method: ('__module__', '__main__')
Not a method: ('__ne__', <slot wrapper '__ne__' of 'object' objects>)
Not a method: ('__new__', <built-in method __new__ of type object at 0x1001e0640>)
Not a method: ('__reduce__', <method '__reduce__' of 'object' objects>)
Not a method: ('__reduce_ex__', <method '__reduce_ex__' of 'object' objects>)
Not a method: ('__repr__', <slot wrapper '__repr__' of 'object' objects>)
Not a method: ('__setattr__', <slot wrapper '__setattr__' of 'object' objects>)
Not a method: ('__sizeof__', <method '__sizeof__' of 'object' objects>)
Not a method: ('__str__', <slot wrapper '__str__' of 'object' objects>)
Not a method: ('__subclasshook__', <method '__subclasshook__' of 'object' objects>)
Not a method: ('__weakref__', <attribute '__weakref__' of 'X' objects>)
Not a method: ('y', <function X.y at 0x1006ee3b0>)

Answer 1

与 inspect 没有特别的区别，但 Python 3 通常参见 here

The concept of “unbound methods” has been removed from the language. When referencing a method as a class attribute, you now get a plain function object.

我对跨平台的建议是:

getmembers(X, predicate=lambda x: isfunction(x) or ismethod(x))