Convert value from specific multidimensional array

问题:

Basically I just would like to know if there is a built-in way of doing this, that might be faster, like maybe with an array_map callback or something:

function array_rekey($a, $column)
{
    $array = array();
    foreach($a as $keys) $array[$keys[$column]] = $keys;
    return $array;
}

回答1:

This should work for you:

Just pass NULL as second argument to array_column() to get the full array back as values and use $column as third argument for the keys.

$result = array_column($arr, NULL, $column);

example input/output:

$arr = [
        ["a" => 1, "b" => 2, "c" => 3],
        ["a" => 4, "b" => 5, "c" => 6],
        ["a" => 7, "b" => 8, "c" => 9],
    ];

$column = "b";
$result = array_column($arr, NULL, $column);
print_r($result);

output:

Array
(
    [2] => Array
        (
            [a] => 1
            [b] => 2
            [c] => 3
        )

    [5] => Array
        (
            [a] => 4
            [b] => 5
            [c] => 6
        )

    [8] => Array
        (
            [a] => 7
            [b] => 8
            [c] => 9
        )

)