metaprogramming - Adding class attributes using a for loop in Python

Question

I was trying to generate a class from a dictionary:

class attr:
    for key in objects_type:
        setattr(attr, key, lambda cl: list())

This gives the error that attr is not defined during the for loop. I know I could write:

class attr:
    pass
for key in objects_type:
    setattr(attr, key, lambda cl: list())

But I am sure I remember seeing code similar to the first example somewhere. Does anyone know if it is possible to write something similar to the first form?

Answer 1

Although it's not very elegant, you can use locals():

>>> class c(object):
...     for i in range(10):
...         locals()['A' + str(i)] = i
... 
>>> c.A0
0
>>> c.A7
7