Question

I have a method that accepts a parameter that can be of several types, and has to do one thing or other depending on the type, but if I check the type of said parameter, I don’t get the ‘real’ type, I always get <type 'instance'>, and that is messing up with my comparisons.

I have something like:

from classes import Class1
from classes import Class2
# Both classes are declared in the same file.
# I don't know if that can be a problem         #
# ... #
def foo(parameter)
    if (type(parameter) == type(Class1()):
    # ... #
    elif (type(parameter) == type(Class2()):
    # ... #

And as type(parameter) returns <type 'instance'> and type(Class1()) is <type 'instance'> as well, it turns out that even if the parameter is an instance of Class2, it is going into the first comparison…

By the way, str(parameter.__class__) properly shows classes.Class1 . I guess I could always use that, but I would like to understand what’s going on… I have made tenths of comparisons like this and all them worked properly…

Thank you!! 🙂

Answer 1

Old-style classes do that. Derive your classes from object in their definitions.