Python and JavaScript equivalent functions but different outputs

Question

I simply rewrote the JS function in Python expecting the output to be the same but turned out different?
Why?
What should I do to the Python function so that it yields the same output as JS?
https://code.sololearn.com/chRNdY58ItaQ/?ref=app
https://code.sololearn.com/W3TYqwq93byp/?ref=app

Answer 1

Because default parameters are not handled the same way in Python and JS ^^

In JS, default argument values are assigned at runtime, while in Python, they are assign at function declaration time.

So, when you do:

def f(p,q=None):

... q will be the same list for each call, while in JS, q will be a new empty list at each call ;)
You rather need to translate the JS behavior by doing:

def f(p,q=None):
q = q or []

Answer 2

Cleared!
Thank you to both visph and Mirielle[Inactive] :)