Python 3.x -> Find Last Occurrence of character in string by using recursion and loop

Question

Could someone teach me how to find the last occurrence of a character in string by using recursion/loop instead of build-in function?

I figured out the loop-method(below), but have no clue about recursion...

def find_last(line,ch):
    if line == None or len(line)==0:
        return -1

    else:
        found_at = 0
        index= 0
        for ch_line in line:
            if ch_line == ch:
                found_at = index
            index+=1
        return found_at

print(find_last("The quick brown fox jumps over the lazy dog", "g"))

returns 42

Many thanks from a python beginner!!

Answer 1

With iteration:

def find_last(line,ch):
    last_seen =-1
    for i in range(len(line)):
        if line[i] == ch:
            last_seen=i
    return last_seen

With recursion:

def find_last_rec(line,ch,count):
    if count==line(len)-1:
        return -1
    elif line[count] ==ch:
        return max(count, find_last_rec(line,ch,count+1))
    else:
        return find_last_rec(line,ch,count+1)


def find_last(line,ch):
    return find_last_rec(line,ch,0)