Online PHP editor | refs for bMknf

<?php error_reporting(E_ALL); $db_results = array( array('cat' => 1, 'id' => 1), array('cat' => 1, 'id' => 2), array('cat' => 2, 'id' => 3), array('cat' => 1, 'id' => 4) ); $category_map = array(); foreach ( $db_results as $row ) { $category_map[ $row['cat'] ][ $row['id'] ] = $row; } print_r($category_map);