PHP 获取数组任意下标key的上一个prev和下一个next下标值
<?php $xoops[1] = '小';$xoops[2] = '孩';$xoops[3] = '子';$xoops[4] = '气';$steps = new Steps();foreach($xoops as $key=>$value){$steps->add($key);}$steps->setCurrent(3);//参数为key值echo '上一个下标：'.$steps->getPrev()."<br />";echo '指定的下标：'.$steps->getCurrent()."<br />";echo '下一个下标：'.$steps->getNext()."<br />";class Steps { private $all; private $count; private $curr; function __construct() { $this->count = 0; } function add($step) { $this->count++; $this->all[$this->count] = $step; } function setCurrent($step) { reset($this->all); for ($i = 1; $i <= $this->count; $i++) { if ($this->all[$i] == $step) break; next($this->all); } $this->curr = current($this->all); } function getCurrent() { return $this->curr; } function getNext() { self::setCurrent($this->curr); return next($this->all); } function getPrev() { self::setCurrent($this->curr); return prev($this->all); }}打印结果：
上一个下标：2指定的下标：3下一个下标：4