PHP Manual: mb

Description

function mb_strpos(
    string $haystack,
    string $needle,
    int $offset = 0,
    ?string $encoding = null
): int|false

Finds position of the first occurrence of needle in the haystack string.

Performs a multi-byte safe strpos() operation based on number of characters. The first character's position is 0, the second character position is 1, and so on.

Parameters

haystack: The string from which to get the position of the first occurrence of needle.
needle: The string to find in haystack. In contrast with strpos(), numeric values are not applied as the ordinal value of a character.
offset: The search offset in characters. If it is not specified, 0 is used. A negative offset counts from the end of the string.
encoding: The encoding parameter is the character encoding. If it is omitted or null, the internal character encoding value will be used.

Return Values

Returns the character position (not byte position) of the first occurrence of needle in the haystack string, counting from 0. Returns false if needle is not found.

Errors/Exceptions

If offset is greater than the length of haystack, a ValueError will be thrown.

As of PHP 8.0.0, a ValueError is thrown if encoding is an invalid encoding. Prior to PHP 8.0.0, an E_WARNING was emitted instead.

Changelog

Version	Description
8.0.0	`needle` now accepts an empty string.
8.0.0	`encoding` is nullable now.
8.0.0	Now throws a ValueError if `encoding` is an invalid encoding. Previously, an `E_WARNING` was emitted and `false` was returned.
7.1.0	Support for negative `offset`s has been added.

Examples

Example #1 mb_strpos() returns a character offset, not a byte offset

<?php
// "🐘" is 4 bytes but 1 character; "é" is 2 bytes but 1 character
$str = "🐘H🐘é";

var_dump(mb_strpos($str, "é"));  // character 3, not byte 9
var_dump(mb_strpos($str, "🐘", 1)); // character 2, skipping the first "🐘"
?>

The above example will output:

int(3)
int(2)

mb_strpos