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

def multi_find (s, r):
    s_len = len(s)
    r_len = len(r)
    n = [] # assume r is not yet found in s

    if s_len >= r_len:
        m = s_len - r_len
        i = 0

        while i < m:
            # search for r in s until not enough characters are left
            if s[i:i + r_len] == r:
                n.append(i)
            i = i + 1
    print (n)

multi_find("abcdefabc. asdli! ndsf acba saa abe?", "abc")

Pretty much just replace n with a list so you can keep adding values to it as you find them. You also need to be incrementing i even when a match is found, it would have been stuck in a loop forever except that you had the while n == -1 constraint that made it stop as soon as a match was found.