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strpos

PHP function Edit on GitHub ✎

(PHP 4, PHP 5, PHP 7, PHP 8)

Find the position of the first occurrence of a substring in a string

Description

strpos(string $haystack, string $needle, int $offset = 0): int|false

Find the numeric position of the first occurrence of needle in the haystack string.

Parameters

haystack

The string to search in.

needle

The string to search for.

Passing an empty string as needle matches at every position. strpos() returns offset when it is specified, or 0 otherwise.

Non-string

offset

If specified, search will start this number of characters counted from the beginning of the string. If the offset is negative, the search will start this number of characters counted from the end of the string.

Return Values

Returns the position of where the needle exists relative to the beginning of the haystack string (independent of offset). Also note that string positions start at 0, and not 1.

Returns false if the needle was not found.

Falseproblem

Errors/Exceptions

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

Changelog

Version	Description
8.0.0	Passing an Integer as `needle` is no longer supported.
7.3.0	Passing an Integer as `needle` has been deprecated.
7.1.0	Support for negative `offset`s has been added.

Examples

Using ===

php

<?php
$mystring = 'abc';
$findme   = 'a';
$pos = strpos($mystring, $findme);

// Note our use of ===.  Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
    echo "The string '$findme' was not found in the string '$mystring'";
} else {
    echo "The string '$findme' was found in the string '$mystring'";
    echo " and exists at position $pos";
}
?>

Using !==

php

<?php
$mystring = 'abc';
$findme   = 'a';
$pos = strpos($mystring, $findme);

// The !== operator can also be used.  Using != would not work as expected
// because the position of 'a' is 0. The statement (0 != false) evaluates
// to false.
if ($pos !== false) {
     echo "The string '$findme' was found in the string '$mystring'";
         echo " and exists at position $pos";
} else {
     echo "The string '$findme' was not found in the string '$mystring'";
}
?>

Using an offset

php

<?php
// We can search for the character, ignoring anything before the offset
$newstring = 'abcdef abcdef';
$pos = strpos($newstring, 'a', 1); // $pos = 7, not 0

echo $pos, PHP_EOL;
?>