Recursive function return None even though print() works

Question

I am trying to return count in this recursive function but it always returns None. When I do print(count) instead of return count it gives me the correct result. Would anyone be able to tell me what I'm doing wrong? Thank you so much in advance :)

count = 0


def count_lowercase(s, low, high):
    global count
    if low > high:
        return count
    else:
        if s[low] == s[low].lower():
            count += 1
        count_lowercase(s, low + 1, high)

you need to `return count_lowercase(s, low+1, high)` – TheLazyScripter Oct 23 '21 at 23:04 — TheLazyScripter, Oct 23 '21 at 23:04
you need to return count_lowercase in the last line – Ulises Bussi Oct 23 '21 at 23:06 — Ulises Bussi, Oct 23 '21 at 23:06

score 4 · Accepted Answer · answered Oct 23 '21 at 23:04

You need to return count_lowercase(s, low + 1, high), otherwise the function simply ends after executing that statement, resulting in None being returned.

count = 0


def count_lowercase(s, low, high):
    global count
    if low > high:
        return count
    else:
        if s[low] == s[low].lower():
            count += 1
        return count_lowercase(s, low + 1, high)

Recursive function return None even though print() works

1 Answers1