FindTheIndexOfTheFirstOccurrenceInAString

Problem

https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/

Solution

Iterate through each character in haystack and check if the substring haystack[i:i + len(needle)] is equal to needle.

Code

def strStr(haystack: str, needle: str) -> int:
    """Find the first occurrence of ``needle`` in ``haystack``.
    """
    for i, char in enumerate(haystack):
        if haystack[i:i + len(needle)] == needle:
            return i
    return -1

Test

>>> from FindTheIndexOfTheFirstOccurrenceInAString import strStr
>>> strStr('hello', 'll')
2
>>> strStr('aaaaa', 'bba')
-1

FindTheIndexOfTheFirstOccurrenceInAString.strStr(haystack: str, needle: str) → int: Find the first occurrence of needle in haystack.