Reference or Value?

[Torsten Mohr]

Hi,

how is the rule in Python, if i pass objects to a function, when is this
done by reference and when is it by value?

def f1(a):
    a = 7

b = 3
f1(b)
print b
=> 3

Integers are obviously passed by value, lists and dicts by reference.

Is there a general rule?  Some common formulation?


Thanks for any hints,
Torsten.