strpos
Category: String Functions
PHP 4+

Description

The strpos function finds the position (index) of the first occurrence of a substring within a string. It returns the numeric position if found, or false if not found. Position numbering starts at zero.

Syntax 

strpos(string $haystack, mixed $needle [, int $offset = 0])

Parameters

ParameterTypeDescription
$haystack string The main string to search within
$needle mixed The value to search for. If a number, treated as ASCII character ordinal
$offset int Optional — search start position. Default: 0

Return Value

Returns the numeric position of the first match, or false if the needle is not found. Always use === (strict comparison) when checking the result, since position 0 is falsy.

Example 

<?php
$text = "Hello, welcome to PHPvillage!";

// Find position of "welcome"
$pos = strpos($text, "welcome");

if ($pos !== false) {
    echo "Found at position: " . $pos; // 7
} else {
    echo "Not found.";
}
?>
Notes
  • This function is case-sensitive. Use stripos() for case-insensitive search.
  • Always compare the return value with !== false, not just != false.
  • To find all occurrences, loop and use the $offset parameter.