Arrays
PHP Manual

key

(PHP 4, PHP 5)

key — Fetch a key from an associative array

Description

mixed key ( array &$array )

key() returns the index element of the current array position.

Example#1 key() example

<?php
$array 
= array(
    
'fruit1' => 'apple',
    
'fruit2' => 'orange',
    
'fruit3' => 'grape',
    
'fruit4' => 'apple',
    
'fruit5' => 'apple');

// this cycle echoes all associative array
// key where value equals "apple"
while ($fruit_name current($array)) {
    if (
$fruit_name == 'apple') {
        echo 
key($array).'<br />';
    }
    
next($array);
}
?>

See also current() and next().


Arrays
PHP Manual