key

(PHP 3, 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().