get class name before init upon class definition

Question

I wonder if there is a way to get the class name automatically upon defining class attribute before initialization

class MyClass(object):
    attribute1 = 1
    attribute2 = 2 # This a simple example, MyClass has many other attributes
    print className # normally one would use self.__class__.__name__ but self or cls are not defined at the level

    def __init__(self):
        a = 1

Purpose

In the framework I am working in, attribute1 and attribute2 are object instances (you will say everything is object oriented in python :) ) I want to set the class name to those attributes prior to MyClass initialization. MyClass get initialized a lot of times and it has much more than 2 attributes which makes the operation very time consuming to do at every initialization

Why would you need it prior to initialization? The class will not run until it is initialized so I don't really see the point. — asdf, Sep 16 '14 at 17:13
You can use a metaclass -- But I'm not sure exactly how much that helps you since you haven't said _why_ you need the class name. Perhaps if you tell us what you're actually trying to accomplish here we can point you in a different direction. — mgilson, Sep 16 '14 at 17:16
It's not clear what you are trying to do, but you should take a look at metaclasses :) — Wolph, Sep 16 '14 at 17:16
In the framework I am working in, attribute1 and attribute2 are object instances (you will say everything is object oriented in python :) ) I want to set the class name to those attributes prior to MyClass initialization. MyClass get initialized a lot of times and it has much more than 2 attributes which makes the operation very time consuming to do at every initialization — Cobry, Sep 16 '14 at 17:26
What does "set the class name to those attributes" mean? Do you mean pass the attributes to the `__init__` function? What *exactly* are you trying to do? — Daniel Roseman, Sep 16 '14 at 17:29

score 0 · Answer 1 · edited May 23 '17 at 11:44

A metaclass can be used to set an attribute with the class name before the class initialises:

class MyClassMeta(type):
    def __init__(self, name, bases, attrs):
        super(MyClassMeta, self).__init__(name, bases, attrs)
        # Set class_name to the name of our class; in this case "MyClass"
        self.class_name = name

class MyClass(object):
    __metaclass__ = MyClassMeta

    def __init__(self):
        # Prints "MyClass"
        print(self.class_name)

See this answer for a detailed explanation of metaclasses.

get class name before init upon class definition

Purpose

1 Answers1