Sort a PHP array based on a subarray.

orderBySubArray.php

<?php

function orderBySubArray( &$array, $new_key = 'order', $order = 'ascending', $start_at = 1 )
{
	$output = array();
	$count = count( $array );
	$i = ( $order == 'ascending' ) ? $start_at : $count;

	for ( $j = 1; $j <= $count; $j++ )
	{
		foreach ( $array as $key => &$item )
		{
			if ( $item[ $new_key ] == $i )
			{
				array_push( $output, $item );
				unset( $array[$key] ); // reduces items to be inspected by 2X on average
				$i = ( $order == 'ascending' ) ? $i + 1 : $i - 1;
				break;
			}
		}
	}
	return $output;
}