Php 在数组迭代期间判断当前元素是否是最后一个元素

发布于05月23日

请帮我把这个伪代码翻译成真正的php代码:

 foreach ($arr as $k => $v)
    if ( THIS IS NOT THE LAST ELEMENT IN THE ARRAY)
        doSomething();

编辑:数组可以有数字键或字符串键

推荐答案

你可以使用PHP的end()

$array = array('a' => 1,'b' => 2,'c' => 3);
$lastElement = end($array);
foreach($array as $k => $v) {
    echo $v . '<br/>';
    if($v == $lastElement) {
         // 'you can do something here as this condition states it just entered last element of an array'; 
    }
}

Update1个

正如@mijoja所指出的，如果您在数组中多次使用相同的值，则上面可能会有问题.下面是它的修复方法.

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2);
//point to end of the array
end($array);
//fetch key of the last element of the array.
$lastElementKey = key($array);
//iterate the array
foreach($array as $k => $v) {
    if($k == $lastElementKey) {
        //during array iteration this condition states the last element.
    }
}

Update2

我发现@onteria_uu的解决方案比我的答案更好，因为它不会修改数组内部指针，我正在更新答案以匹配他的答案.

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2);
// Get array keys
$arrayKeys = array_keys($array);
// Fetch last array key
$lastArrayKey = array_pop($arrayKeys);
//iterate array
foreach($array as $k => $v) {
    if($k == $lastArrayKey) {
        //during array iteration this condition states the last element.
    }
}

谢谢你@onteria_

Update3

As pointed by @CGundlach PHP 7.3 introduced array_key_last which seems much better option if you are using PHP >= 7.3

$array = array('a' => 1,'b' => 2,'c' => 3);
$lastKey = array_key_last($array);
foreach($array as $k => $v) {
    echo $v . '<br/>';
    if($k == $lastKey) {
         // 'you can do something here as this condition states it just entered last element of an array'; 
    }
}