(PHP 3, PHP 4, PHP 5)
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().