PHP - 按键检索子数组值

Question

Given the following structure:

Array
(
    [0] => Array
        (
            [id_field] => 100
        )

    [1] => Array
        (
            [id_field] => 200
        )

    [2] => Array
        (
            [id_field] => 382
        )

    [3] => Array
        (
            [id_field] => 509
        )

    [4] => Array
        (
            [id_field] => 636
        )

    [5] => Array
        (
            [id_field] => 763
        )

    [6] => Array
        (
            [id_field] => 890
        )

    [7] => Array
        (
            [id_field] => 1017
        )

)

Is there a built in array method which can grab all id_field values?

I can loop over them for sure, but think maybe there is a built in that i cannot see in the manual that already does this?

Answer 1

If you have PHP 5.5.0+, you could use array_column():

$result = array_column($data, 'id_field');

If you're running an older PHP version, you can use the userland implentation of this function (written by the same author who wrote the original array_column() function).

However, for simple use-cases, this can be implemented as function using a simple foreach loop. This isn't guaranteed to handle all possible cases, but it should be enough for the most part.

function array_column2(array $arr, $column) {
    $result = array();
    foreach ($arr as $key => $value) {
        $result[] = $arr[$column];
    }
    return $result;
}