Voting

The Note You're Voting On

20 years ago
Sometimes you need to pick certain non-integer and/or non-sequential keys out of an array. Consider using the array_pick() implementation below to pull specific keys, in a specific order, out of a source array:

<?php

$a = array ('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4);
$b = array_pick($a, array ('d', 'b'));

// now:
// $a = array ('a' => 1, 'c' => '3');
// $b = array ('d' => 4, 'b' => '2');

function &array_pick(&$array, $keys)
{
    if (! is_array($array)) {
        trigger_error('First parameter must be an array', E_USER_ERROR);
        return false;
    }

    if (! (is_array($keys) || is_scalar($keys))) {
        trigger_error('Second parameter must be an array of keys or a scalar key', E_USER_ERROR);
        return false;
    }

    if (is_array($keys)) {
        // nothing to do
    } else if (is_scalar($keys)) {
        $keys = array ($keys);
    }

    $resultArray = array ();
    foreach ($keys as $key) {
        if (is_scalar($key)) {
            if (array_key_exists($key, $array)) {
                $resultArray[$key] = $array[$key];
                unset($array[$key]);
            }
        } else {
            trigger_error('Supplied key is not scalar', E_USER_ERROR);
            return false;
        }
    }

    return $resultArray;
}

?>
<< Back to user notes page