Leetcode Day 尋找字串中第一次出現的索引解釋

Input: haystack = "sadbutsad", needle = "sad"
Output: 0
Explanation: "sad" occurs at index 0 and 6.
The first occurrence is at index 0, so we return 0.

Input: haystack = "leetcode", needle = "leeto"
Output: -1
Explanation: "leeto" did not occur in "leetcode", so we return -1.

if needle in haystack:
    return haystack.index(needle)
else:
    return -1

class Solution:
    def strStr(self, haystack: str, needle: str) -> int:
        return haystack.index(needle) if needle in haystack else -1