python - 指向方法的类变量的行为不同

Question

类变量的行为与常规变量不同。当将类变量作为方法调用时，它不会像普通变量一样被调用:

#!/usr/bin/env python
def func():
    print 'func called'

class MyClass(object):
    FUNC = func

    def call_func(self):
        MyClass.FUNC()

instance = MyClass()
instance.call_func()

产品:

Traceback (most recent call last):
  File "main.py", line 12, in <module>
    instance.call_func()
  File "main.py", line 9, in call_func
    MyClass.FUNC()
TypeError: unbound method func() must be called with MyClass instance as first argument (got nothing instead)

Answer 1

要使其按预期工作，您必须使用 staticmethod() 修饰 FUNC:

#!/usr/bin/env python
def func():
    print 'func called'

class MyClass(object):
    FUNC = staticmethod(func)

    def call_func(self):
        MyClass.FUNC()

instance = MyClass()
instance.call_func()