Finding a string multiple times in another String - Python

Question

I\'m trying to see if a string exists in another string with out using Python\'s predefined functions such as find and index..

Right now what my function takes 2 strings

Answer 1

Note: I think this answer here is still a good "teaching answer", I have submitted a better solution elsewhere in this thread, without recursion.

def multi_find(s, r, start=0):
    if start >= len(s): 
        return []
    if s.startswith(r, start):
        return [start] + multi_find(s, r, start+1)
    else:
        return multi_find(s, r, start+1)

This allows you to pass an optional start position to begin the search in s.

This solution is recursive, which may or may not be the fastest implementation, but it is correct and I believe it makes the code easy to identify each of the three possibilities at each position of s:

1. end of s
2. found another r
3. didn't find another r