有没有更好的pythonic方法来重写while循环？

Question

I wrote this function to do the strStr function:

def strStr(haystack: str, needle: str) -> int:
    if not needle:
        return 0

    len_h = len(haystack)
    len_n = len(needle)

    if len_n > len_h:
        return -1

    index_h = 0
    index_n = 0
    matched_count = 0
    while index_h < len_h and index_n < len_n:
        v_h = haystack[index_h]
        v_n = needle[index_n]
        if v_h != v_n:
            index_h = index_h - matched_count + 1
            index_n = 0
            matched_count = 0
        else:
            index_h += 1
            index_n += 1
            matched_count += 1

        if index_n == len_n:
            return (index_h - len_n)

    return -1


print(strStr('hello', 'll'))
print(strStr('mississippi', 'issip'))

The while loop is the C or Java way. I tried to use for... in range in Python. But failed to do it, because I need to update the indexes based on conditions. The for loop in Python doesn't seem to work. Still, is there a python way to replace the while loop?

Answer 1

Python has a string method.find() that's implemented using the Boyer-Moore method ( https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore%E2%80%93Horspool_algorithm ).

This contains a couple of while loops. So I would say it's a reasonably pythonic way to do it.