@looopTools

Fair enough. Because recursion always has a limit, in any language, the tutorials probably assume you're aware of this already. The specific limit in Python is adjustable, but there's no way to eliminate it altogether.

Do the tutorials actually include data/examples that run into the recursion limit? Or is it only when applying code like that to other data that you run into issues?

I ask because the easiest way to smash the limit is to create a cyclic data structure, which is trivial in Python. If you naively recurse such an object, it goes on forever - until it hits the configured limit or the machine runs out of memory, anyways. i.e. this case:

>>> foo = ["bar"]
>>> foo.append(foo)
>>> foo
['bar', [...]]

If you think it's possible your recursion code might have to deal with something like this, you usually end up keeping track of the objects you've already processed, and skip them if you see the same object again (typically by the object ID).

In many cases, you can also rewrite recursive code so that it's not recursive, and cannot run into this problem. As a bonus, problems that can be refactored this way usually run faster without the recursion.

#recursion #stack #boom #limit