如何在PHP中打印或回显数组的索引 [英] How to print or echo the array index of in PHP

问题描述

我正在尝试完成我的任务，这是现在要做的最后一件事.

I'm trying to complete my assignment and this is the last thing to do now.

我知道我是否要打印整个数组，我可以使用foreach和许多不同的方法来打印整个数组

I know if I want to print the whole array I can just use foreach and many different method to print the entire array

foreach($v as $k=>$variable_name) { echo "<p> This is index of $k. value is $variable_name <br/></p>";}

但是，如果我只想单独打印每个索引怎么办?

But what if I want to only print each index separately?

我想在每种表格下显示错误消息，所以这就是为什么我希望它们分开的原因.

I want to do the error message under each form so that is why I want each of them separate.

我尝试使用$v[0]，但没有任何显示.

I tried with $v[0] and nothing appear.

有什么花招或我想念的东西吗?

is there a trick or something am I missing?

推荐答案

如果您正在谈论关联数组，则需要直接获取索引:

If you're talking about an associative array, you need to fetch the index directly:

示例:

$array = array ('test' => 'value1', 'test2' => 'value2');   
echo $array['test']; // value1

您可以执行print_r($ array)来查看格式正确的数组结构:

You can do a print_r($array) to see the array structure nicely formatted:

<pre>
<?php print_r($array);?>
</pre>

您正在做的是通过其数字索引来获取值，例如in

What you're doing instead is fetch a value by its numerical index, like in

$array = array('test','test2','test3');
echo $array[0];  // test

请注意，您可以使用 array_key_exists():

var_dump(array_key_exists('test2',$array));  // (bool) TRUE

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