我有一个带key =>的数组值,我想收到给定数组键的上一个和下一个条目。
示例:
$array = array(
'one' => 'first',
'two' => 'second',
'three' => '3rd',
'four' => '4th'
)
当我收到指定的密钥'two'
时,我希望收到条目$array['one']
和$array['three']
,是否有任何不错的无预告解决方案?
答案 0 :(得分:3)
您要查找的两个功能是next()和prev()。本机PHP函数可以完全满足您的要求:
$previousPage = prev($array);
$nextPage = next($array);
这些函数移动内部指针,例如,如果你在$ array ['two']并使用prev($ array),那么你现在在$ array ['one']上。我得到的是,如果你需要得到一个和三个,那么你需要调用next()两次。
答案 1 :(得分:1)
$array = array(
'one' => 'first',
'two' => 'second',
'three' => '3rd',
'four' => '4th'
);
function getPrevNext($haystack,$needle) {
$prev = $next = null;
$aKeys = array_keys($haystack);
$k = array_search($needle,$aKeys);
if ($k !== false) {
if ($k > 0)
$prev = array($aKeys[$k-1] => $haystack[$aKeys[$k-1]]);
if ($k < count($aKeys)-1)
$next = array($aKeys[$k+1] => $haystack[$aKeys[$k+1]]);
}
return array($prev,$next);
}
var_dump(getPrevNext($array,'two'));
var_dump(getPrevNext($array,'one'));
var_dump(getPrevNext($array,'four'));
答案 2 :(得分:0)
您可以尝试使用SPL CachingIterator的实现来解决问题。
答案 3 :(得分:0)
您可以定义自己的类来处理基本数组操作:
以下是adityabhai发布的一个例子[at] gmail com [Aditya Bhatt] 09-May-2008 12:14发布于php.net
<?php
class Steps {
private $all;
private $count;
private $curr;
public function __construct () {
$this->count = 0;
}
public function add ($step) {
$this->count++;
$this->all[$this->count] = $step;
}
public function setCurrent ($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);
}
public function getCurrent () {
return $this->curr;
}
public function getNext () {
self::setCurrent($this->curr);
return next($this->all);
}
public function getPrev () {
self::setCurrent($this->curr);
return prev($this->all);
}
}
?>
Demo Example:
<?php
$steps = new Steps();
$steps->add('1');
$steps->add('2');
$steps->add('3');
$steps->add('4');
$steps->add('5');
$steps->add('6');
$steps->setCurrent('4');
echo $steps->getCurrent()."<br />";
echo $steps->getNext()."<br />";
echo $steps->getPrev()."<br />";
$steps->setCurrent('2');
echo $steps->getCurrent()."<br />";
echo $steps->getNext()."<br />";
echo $steps->getPrev()."<br />";
?>