> ``` > public function treeBack($data,$pid){ > foreach($data as $k=>$v){ > if($v['pid'] == $pid){ > $v['child'] = $this->treeBack($data,$v['id']); > $tree[] = $v; > unset($data[$k]); > } > } > return $tree; > } > ``` - 如上代碼，這是一段很經典的無限遞歸循環邏輯，但是當數據量超過2000 - 3000行時，效率大打折扣，經過我們的實際應用測試，在沒有優化這段代碼之前，遞歸所耗費的時間是 2s 左右 - 但是經過優化之后，遞歸邏輯耗費的時間僅僅只有 86ms 左右 - OK，貼出下優化后的代碼再來分析 > ``` > public function treeBack($data, $pidKey='pid', $idKey = 'id', $childKey='child') { > $grouped = array(); > foreach ($flat as $sub){ > $grouped[$sub[$pidKey]][] = $sub; > } > $fnBuilder = function($siblings) use (&$fnBuilder, $grouped, $idKey, $childKey) { > foreach ($siblings as $k => $sibling) { > $id = $sibling[$idKey]; > if(isset($grouped[$id])) { > $sibling[$childKey] = $fnBuilder($grouped[$id]); > usort($sibling[$childKey], function($a, $b) use ($childKey) { > if ($a[$childKey] == $b[$childKey]) { > return 0; > } > return ($a['weight'] < $b['weight']) ? -1 : 1; > }); > } > $siblings[$k] = $sibling; > } > return $siblings; > }; > $tree = $fnBuilder($grouped[0]); > return $tree; > } > ``` - 恩，你沒有看錯,將數據重新構造，然后進行匿名函數循環