Online PHP editor | output for 1KEPR

<?php $categories = array( array( 'parent_id' => 0, 'categories_id' => 1, ), array( 'parent_id' => 0, 'categories_id' => 2, ), array( 'parent_id' => 1, 'categories_id' => 11, ), array( 'parent_id' => 1, 'categories_id' => 111, ), array( 'parent_id' => 2, 'categories_id' => 22, ), ); foreach ($categories as $category) { } function build($category, &$tree = array()) { if ($category['parent_id'] == 0) { $category = array( $category['categories_id'] => $category, ); $tree = array_merge($tree, $category); return $tree; } foreach ($tree as $cate_id => $cate) { if ($category['parent_id'] == $cate_id) { $tree[$cate_id]['childs'] = $category; } if (is_array($cate)) { return build($cate, $tree); } } return $tree; }