如何使用另一个数组通过键过滤数组 [英] How to filter an array by keys using another array

问题描述

我现在在我的项目上工作了几个小时，我从早期的阵列中获取了一些密钥，我想循环到我的新阵列，并从早期的阵列中选择我拥有的密钥的值.

I working now for a couple of hours on my project, i have some key's from a early array that i want to loop to my new array and pick the value of the key's that i have from the early array.

早期数组:

$old_keys = ['key1','key2','key3'];

新数组:

$result = ['key1' => 'foo', 'key2' => 'bar', 'key6' => 'ipsum'];

我想要的输出是:

$output = ['foo', 'bar'];

这就是我做的:

foreach ($old_keys as $old_key) {

    $output[] = array_column($result, $old_key);

}
return $output;

我做错了什么，因为我得到的一切都是空数组

What did i wrong because everything what i get is a empty array

非常感谢！

更新:

$keys = array_flip($old_keys);

$output = array_values(array_intersect_key($result, $keys));

echo '<pre>';
var_dump($output);

现在$ output中填充了$ result的多维数组，但是值'foo'和'bar'在此多维数组的第二级中.问题是，我只能得到该数组的第一级，而不能得到第二级.

The $output is now filled with the multidimensional array of $result, but the values 'foo' and 'bar' are in the second level of this multidimensional array. The problem is, i get only the first level of this array and not the second level.

输出示例:

[
 [0] => string
 [1] => string
 [
  [key1] => foo
  [key2] => bar
 ]
]

我想要的是:

[
 [0] => string
 [1] => string
 [3] => foo
 [4] => bar
]

解决方案:

$flat = iterator_to_array(new RecursiveIteratorIterator(new RecursiveArrayIterator($result)), true);

推荐答案

使用 $ old_keys 过滤 $ result 数组，但使用 $ old_keys 值作为键:

Filter the $result array using $old_keys, but use the $old_keys values as keys:

$old_keys = array_flip(['key1','key2','key3']);
$result = ['key1' => 'foo', 'key2' => 'bar', 'key6' => 'ipsum'];
$output=array_intersect_key($result,$old_keys);
print_r($output);

如果要在结果中为键重新编制索引，请将 $ output 声明替换为:

If you want to re-index the keys in the result, replace the $output declaration with:

$output=array_values(array_intersect_key($result,$old_keys));

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