在数组迭代期间检查当前元素是否为最后一个元素

问题描述

限时删除！！

请帮助我将此伪代码转换为真实的php代码:

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

数组可能具有数字键或字符串键

解决方案

您可以使用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';
    }
}

更新1

如@Mijoja所指出的，如果在数组中多次具有相同的值，则上面可能会有问题.以下是解决方法.

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2);
//point to end of the array
end($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_的解决方案比我回答的要好，因为它不修改数组内部指针，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@onteria _

Update3

正如@CGundlach指出的那样，PHP 7.3引入了array_key_last，如果您使用的是PHP> = 7.3，则似乎是更好的选择

$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';
    }
}

Please help me to translate this pseudo-code to real php code:

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

Edit: the array may have numerical or string keys

解决方案

you can use PHP's 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

as pointed out by @Mijoja the above could will have problem if you have same value multiple times in array. below is the fix for it.

$array = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 2);
//point to end of the array
end($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

I found solution by @onteria_ to be better then what i have answered since it does not modify arrays internal pointer, i am updating the answer to match his answer.

$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.
    }
}

Thank you @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';
    }
}

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