Python 中的静态方法？

Question

Is it possible to have static methods in Python so I can call them without initializing a class, like:

ClassName.StaticMethod ( )

转载于:https://stackoverflow.com/questions/735975/static-methods-in-python

Answer 1

Yep, using the staticmethod decorator

class MyClass(object):
    @staticmethod
    def the_static_method(x):
        print x

MyClass.the_static_method(2) # outputs 2

Note that some code might use the old method of defining a static method, using staticmethod as a function rather than a decorator. This should only be used if you have to support ancient versions of Python (2.2 and 2.3)

class MyClass(object):
    def the_static_method(x):
        print x
    the_static_method = staticmethod(the_static_method)

MyClass.the_static_method(2) # outputs 2

This is entirely identical to the first example (using @staticmethod), just not using the nice decorator syntax

Finally, use staticmethod() sparingly! There are very few situations where static-methods are necessary in Python, and I've seen them used many times where a separate "top-level" function would have been clearer.

---

The following is verbatim from the documentation::

A static method does not receive an implicit first argument. To declare a static method, use this idiom:

class C:
    @staticmethod
    def f(arg1, arg2, ...): ...

The @staticmethod form is a function decorator – see the description of function definitions in Function definitions for details.

It can be called either on the class (such as C.f()) or on an instance (such as C().f()). The instance is ignored except for its class.

Static methods in Python are similar to those found in Java or C++. For a more advanced concept, see classmethod().

For more information on static methods, consult the documentation on the standard type hierarchy in The standard type hierarchy.

New in version 2.2.

Changed in version 2.4: Function decorator syntax added.