Question

I want to determine which attribute to look-up dynamicaly,
Consider below python code:

def f(x, a):
    return x.a

class X:
    b = 4

x = X()
print(f(x, b))

If python had this property, above code should print 4.

Is there way to do it in any language?
I cannot conceive a way with C++ templates or dynamic typing.

Answer 1

I don’t think you can dynamically access attributes of objects in the way you are attempting. the built-in function getattr will allow you to do this. As marcin suggested you can just replace f with getattr

http://docs.python.org/library/functions.html#getattr

def f(x, a)
  return getattr(x, a)

or

class X:
    b = 4

getattr(x, a)

print(getattr(x, "b"))