In Python, how do I reference a class generically in a static way, like PHP's "self" keyword?

Question

PHP classes can use the keyword “self” in a static context, like this:

<?php
class Test {
  public static $myvar = 'a';
  public static function t() {
     echo self::$myvar; // Generically reference the current class.
     echo Test::$myvar; // Same thing, but not generic.
  }
}
?>

Obviously I can’t use “self” in this way in Python because “self” refers not to a class but to an instance. So is there a way I can reference the current class in a static context in Python, similar to PHP’s “self”?

I guess what I’m trying to do is rather un-pythonic. Not sure though, I’m new to Python. Here is my code (using the Django framework):

class Friendship(models.Model):
  def addfriend(self, friend):
    """does some stuff"""

  @staticmethod # declared "staticmethod", not "classmethod"
  def user_addfriend(user, friend): # static version of above method
    userf = Friendship(user=user) # creating instance of the current class
    userf.addfriend(friend) # calls above method

# later ....
Friendship.user_addfriend(u, f) # works

My code works as expected. I just wanted to know: is there a keyword I could use on the first line of the static method instead of “Friendship”?

This way if the class name changes, the static method won’t have to be edited. As it stands the static method would have to be edited if the class name changes.

Asked By: Eddified

||

Source

Answer 1

In all cases, self.__class__ is an object’s class.

http://docs.python.org/library/stdtypes.html#special-attributes

In the (very) rare case where you are trying to mess with static methods, you actually need classmethod for this.

class AllStatic( object ):
    @classmethod
    def aMethod( cls, arg ):
        # cls is the owning class for this method 

x = AllStatic()
x.aMethod( 3.14 )

Answered By: S.Lott

Answer 2

This should do the trick:

class C(object):
    my_var = 'a'

    @classmethod
    def t(cls):
        print cls.my_var

C.t()

Answered By: Bastien Léonard

In Python, how do I reference a class generically in a static way, like PHP's "self" keyword?

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