Python class variable name vs __name__

Question

I'm trying to understand the relationship between the variable a Python class object is assigned to and the __name__ attribute for that class object. For example:

In [1]: class Foo(object):
   ...:     pass
   ...: 

In [2]: Foo.__name__ = 'Bar'

In [3]: Foo.__name__
Out[3]: 'Bar'

In [4]: Foo
Out[4]: __main__.Bar

In [5]: Bar
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-5-962d3beb4fd6> in <module>()
----> 1 Bar

NameError: name 'Bar' is not defined

So it seems like I have changed the __name__ attribute of the class but I can't refer to it by that name. I know this is a bit general but could someone explain the relationship between Foo and Foo.__name__?

Answer 1

It's simple. There is no relationship at all.

When you create a class a local variable is created with name you used, pointing at the class so you can use it.

The class also gets an attribute __name__ that contains the name of that variable, because that's handy in certain cases, like pickling.

You can set the local variable to something else, or change the __name__ variable, but then things like pickling won't work, so don't do that.