Question

I want to assign a class attribute via a string object – but how?

Example:

class test(object):   pass  a = test() test.value = 5 a.value # -> 5 test.__dict__['value'] # -> 5  # BUT: attr_name = 'next_value'  test.__dict__[attr_name] = 10 # -> 'dictproxy' object does not support item assignment 

Answer 1

There is a builtin function for this:

setattr(test, attr_name, 10) 

Reference: http://docs.python.org/library/functions.html#setattr

Example:

>>> class a(object): pass >>> a.__dict__['wut'] = 4 Traceback (most recent call last):   File '<stdin>', line 1, in <module> TypeError: 'dictproxy' object does not support item assignment >>> setattr(a, 'wut', 7) >>> a.wut 7