Synopsis

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

Description

System Message: ERROR/3 (function.strpos.rst, line 8)

Unknown directive type "signature".

.. signature::
    int function strpos(
        string $haystack,
        mixed $needle,
        int $offset = 0
    )

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

Parameters

$haystack: The string to search in.
$needle: If $needle is not a string, it is converted to an integer and applied as the ordinal value of a character.
$offset: If specified, search will start this number of characters counted from the beginning of the string. Unlike FUNCTION:strrpos and FUNCTION:strripos, the offset cannot be negative.

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.

Warning

This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

EXAMPLES

Using _===_

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

Notes

Note

This function is binary-safe.