I am trying to make a function which return max from nested list?

Question

I wrote this and its working fine with everything but when I have an empty list in a given list(given_list=[[],1,2,3]) it saying index is out of range. Any help?

Answer 1

I assume that the max element of an empty list is negative infinity.

This assumption will deal with the cases like [], [1,2,[],5,4,[]]

def find_max(L):

    if len(L) == 0:
        return float("-inf")
    elif len(L) == 1:
        if isinstance(L[0], list):
            return find_max(L[0])
        else:
            return L[0]
    elif len(L) == 2:
        if isinstance(L[0], list):
            firstMax = find_max(L[0])
        else:
            firstMax = L[0]
        if isinstance(L[1], list):
            lastMax = find_max(L[1])
        else:
            lastMax = L[1]
        if firstMax > lastMax:
            return firstMax
        else:
            return lastMax
    else:
        if isinstance(L[0], list):
            firstMax = find_max(L[0])
            lastMax = find_max(L[1:])
            if firstMax > lastMax:
                return firstMax
            else:
                return lastMax
        else:
            lastMax = find_max(L[1:])
            if L[0] > lastMax:
                return L[0]
            else:
                return lastMax