strpos

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

strposFind 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.

Prior to PHP 8.0.0, if needle is not a string, it is converted to an integer and applied as the ordinal value of a character. This behavior is deprecated as of PHP 7.3.0, and relying on it is highly discouraged. Depending on the intended behavior, the needle should either be explicitly cast to string, or an explicit call to chr() should be performed.

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.

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.

Changelog

VersionDescription
8.0.0needle now accepts an empty string.
8.0.0 Passing an int as needle is no longer supported.
7.3.0 Passing an int as needle has been deprecated.
7.1.0 Support for negative offsets has been added.

Examples

Example #1 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";
}
?>

Example #2 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'";
}
?>

Example #3 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.

See Also

  • stripos() - Find the position of the first occurrence of a case-insensitive substring in a string
  • str_contains() - Determine if a string contains a given substring
  • str_ends_with() - Checks if a string ends with a given substring
  • str_starts_with() - Checks if a string starts with a given substring
  • strrpos() - Find the position of the last occurrence of a substring in a string
  • strripos() - Find the position of the last occurrence of a case-insensitive substring in a string
  • strstr() - Find the first occurrence of a string
  • strpbrk() - Search a string for any of a set of characters
  • substr() - Return part of a string
  • preg_match() - Perform a regular expression match
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