Learning Recursive functions and my return won't hit when criteria is met

Question

I'm working through an algorithm and wanted to try to use recursive functions to solve it. In doing so I have this code:

def persistence(n, count=0):
    holder = 1
    if n < 9:
        return count
    num = [int(a) for a in str(n)]
    print(f'num {num}')

    for i in num:
        holder = holder * i
        print(f'holder {holder}')

    count += 1
    print(f'count {count}')

    if holder < 9:
        print(f'The final count is {count}')
        return count
    else:
        persistence(holder, count)

    persistence(39)

The problem is the return in the If statement never gets called when the criteria is met:

    if holder < 9:
    print(f'The final count is {count}')
    return count
else:
    persistence(holder, count)

It will run the print but never run the return and instead recalls the functions until nothing is returned.

Answer 1

I think you just need to return the result of the recursive call in the final line of the function persistence():

def persistence(n, count=0):
    holder = 1
    if n < 9:
        return count
    num = [int(a) for a in str(n)]
    print(f'num {num}')

    for i in num:
        holder = holder * i
        print(f'holder {holder}')

    count += 1
    print(f'count {count}')

    if holder < 9:
        print(f'The final count is {count}')
        return count
    else:
        return persistence(holder, count)

persistence(39)

Output:

num [3, 9]
holder 3
holder 27
count 1
num [2, 7]
holder 2
holder 14
count 2
num [1, 4]
holder 1
holder 4
count 3
The final count is 3