Question

Suppose you have a python method that gets a type as parameter; is it possible to determine if the given type is a nested class?
E.g. in this example:

def show_type_info(t):     print t.__name__     # print outer class name (if any) ...  class SomeClass:     pass  class OuterClass:     class InnerClass:         pass  show_type_info(SomeClass) show_type_info(OuterClass.InnerClass) 

I would like the call to show_type_info(OuterClass.InnerClass) to show also that InnerClass is defined inside OuterClass.

Answer 1

AFAIK, given a class and no other information, you can’t tell whether or not it’s a nested class. However, see here for how you might use a decorator to determine this.

The problem is that a nested class is simply a normal class that’s an attribute of its outer class. Other solutions that you might expect to work probably won’t — inspect.getmro, for example, only gives you base classes, not outer classes.

Also, nested classes are rarely needed. I would strongly reconsider whether that’s a good approach in each particular case where you feel tempted to use one.