解析PHP標準庫SPL數據結構

SPL提供了雙向鏈表、堆棧、隊列、堆、降序堆、升序堆、優先級隊列、定長數組、對象容器

SplQueue 隊列類

進出異端，先進先出

<?php$obj = new SplQueue();//插入一個節點到top位置$obj->enqueue(1); $obj->enqueue(2); $obj->enqueue(3);/** SplQueue Object (     [flags:SplDoublyLinkedList:private] => 4     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 1             [1] => 2             [2] => 3         )  ) */$obj->offsetSet(0,'C');/** SplQueue Object (     [flags:SplDoublyLinkedList:private] => 4     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 'C'             [1] => 2             [2] => 3         )  ) */$obj->rewind();//從隊列中返回并刪除bottom位置的元素$obj->dequeue();/** 'C'  SplQueue Object (     [flags:SplDoublyLinkedList:private] => 4     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 2             [1] => 3         )  ) */復制代碼

SplStack 堆棧類

單端進出時，后進先出，先進后出

$obj = new SplStack();/** SplStack Object (     [flags:SplDoublyLinkedList:private] => 6     [dllist:SplDoublyLinkedList:private] => Array         (         )  ) *///向堆棧放入一個節點到top位置$obj->push(1); $obj->push(2); $obj->push(3);/** SplStack Object (     [flags:SplDoublyLinkedList:private] => 6     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 1             [1] => 2             [2] => 3         )  ) *///堆棧的offset = 0 是Top所在的位置，offset = 1 是top節點靠近bottom位置的相鄰節點$obj->offsetSet(0,'C');/** SplStack Object (     [flags:SplDoublyLinkedList:private] => 6     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 1             [1] => 2             [2] => 'C'         )  ) */$obj->offsetSet(1,'B');/** SplStack Object (     [flags:SplDoublyLinkedList:private] => 6     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 1             [1] => 'B'             [2] => 'C'         )  ) *///堆棧的rewind使指針指向top節點，而雙向鏈表的rewind指向bottom節點$obj->rewind();//堆棧的next是使指針向bottom方向相鄰的節點移動一位，而鏈表是向top方向移動$obj->next();//遍歷堆棧$obj->rewind();while($obj->valid()){    echo $obj->key().'=>'.$obj->current();     $obj->next(); }/** 2=>'C' 1=>'B' 0=>1 *///從堆棧中取出top位置的節點并刪除$obj->pop();復制代碼

SplDoublyLinkedList 雙向鏈表類

$obj = new SplDoublyLinkedList();//SplDoublyLinkedList Object ( [flags:SplDoublyLinkedList:private] => 0 [dllist:SplDoublyLinkedList:private] => Array ( ) )//把新的節點數據添加到鏈表的頂部Top$obj->push(1); $obj->push(2); $obj->push(3);//把新的節點數據添加到鏈表底部bottom$obj->unshift(4);/** SplDoublyLinkedList Object (     [flags:SplDoublyLinkedList:private] => 0     [dllist:SplDoublyLinkedList:private] => Array         (             [0] => 4             [1] => 1             [2] => 2             [3] => 3         )  ) *///在沒有調用rewind()方法之前輸出為nullecho 'current'.$obj->current();//輸出: null//把指針指向bottom節點$obj->rewind();//獲取當前指針指向的節點$obj->current();//輸出: 4//將執行挪到下一個$obj->next(); $obj->current();//輸出: 1$obj->prev(); $obj->current();//輸出: 4//越界了$obj->next(); $obj->next(); $obj->next(); $obj->next(); $obj->current();//輸出: null//判斷當前節點是否有效$obj->valid()//輸出： false$obj->prev(); $obj->valid()//輸出： true$obj->shift();//把top節點從鏈表中刪除并返回$obj->pop();//輸出 3//把bottom節點從鏈表中刪除并返回$obj->shift();//輸出 4//返回top節點$obj->top();//返回bottom節點$obj->bottom();復制代碼

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