Static methods - How to call a method from another method?

问题

When I have regular methods for calling another method in a class, I have to do this

class test:
    def __init__(self):
        pass
    def dosomething(self):
        print "do something"
        self.dosomethingelse()
    def dosomethingelse(self):
        print "do something else"

but when I have static methods I can't write

self.dosomethingelse()

because there is no instance. How do I have to do in Python for calling an static method from another static method of the same class?

Edit: what a mess. Ok, I edited back the question to the original question. I already have the answer to the second question that's in Peter Hansen's comment. If you think I should open another question for an answer I already have, plz tell me.

回答1:

class.method should work.

class SomeClass:
  @classmethod
  def some_class_method(cls):
    pass

  @staticmethod
  def some_static_method():
    pass

SomeClass.some_class_method()
SomeClass.some_static_method()

回答2:

How do I have to do in Python for calling an static method from another static method of the same class?

class Test() :
    @staticmethod
    def static_method_to_call()
        pass

    @staticmethod
    def another_static_method() :
        Test.static_method_to_call()

    @classmethod
    def another_class_method(cls) :
        cls.static_method_to_call()

回答3:

NOTE - it looks like the question has changed some. The answer to the question of how you call an instance method from a static method is that you can't without passing an instance in as an argument or instantiating that instance inside the static method.

What follows is mostly to answer "how do you call a static method from another static method":

Bear in mind that there is a difference between static methods and class methods in Python. A static method takes no implicit first argument, while a class method takes the class as the implicit first argument (usually cls by convention). With that in mind, here's how you would do that:

If it's a static method:

test.dosomethingelse()

If it's a class method:

cls.dosomethingelse()

回答4:

OK the main difference between class methods and static methods is:

class method has its own identity, that's why they have to be called from within an INSTANCE.
on the other hand static method can be shared between multiple instances so that it must be called from within THE CLASS

回答5:

you cant call non-static methods from static methods but by creating an instance inside the static method.... it should work like that

class test2(object):
    def __init__(self):
        pass

    @staticmethod
    def dosomething():
        print "do something"
        #creating an instance to be able to call dosomethingelse(),or you may use any existing instace
        a=test2()
        a.dosomethingelse()

    def dosomethingelse(self):
        print "do something else"

test2.dosomething()

hope that will help you :)

回答6:

If these don't depend on the class or instance then why not just make them a function? As this would seem like the obvious solution. Unless of course you think it's going to need to be overwritten, subclass etc. If so then the previous answers are the best bet. Fingers crossed I wont get marked down for merely offering an alternative solution that may or may not fit someones needs ;).

As the correct answer will depend on the use case of the code in question ;) Enjoy

来源：https://stackoverflow.com/questions/1859959/static-methods-how-to-call-a-method-from-another-method

标签

python

static-methods