make assoc

gistfile1.php

<?php
/**
 * @param        $arr
 * @param string $key
 *
 * @return void
 */
function make_assoc(&$arr, $key = 'id')
{
	$tmp = $arr;

	$max  = count($arr);
	$kold = array();
	$knew = array();
	for ($a = 0; $a < $max; $a ++) {
		$kold[] = $a;
		if (isset($tmp[$a][$key])) {
			$knew[]              = $tmp[$a][$key];
			$arr[$tmp[$a][$key]] = $tmp[$a];
		}
	}

	unset($tmp);

	$dif = array_diff($kold, $knew);
	foreach ($dif as $d) unset($arr[$d]);
}