How can I use getattr to access an attribute within an attribute?

Question

What I have is a value found in:

value.number.odd = 7

number.odd is an input by the user, in x.

and so if x='number.odd', I was hoping that:

getattr(value, x)

would display what value.number.odd would, but it doesn't. Instead I get:

AttributeError: missing attribute number.odd

EDIT:

Input x can also be something like X='number', or 'number.negative.prime'

Answer 1

You can use reduce for this (functools.reduce in Python 3.x):

reduce(getattr, x.split('.'), value)

See a demonstration below:

>>> class A:
...     def __init__(self):
...         self.odd = 7
...
>>> class B:
...     def __init__(self):
...         self.number = A()
...
>>> value = B()
>>> value.number.odd
7
>>> x = 'number.odd'
>>> reduce(getattr, x.split('.'), value)
7
>>>