将特定多维数组键的值转换为以原始数组为值的新数组中的键 [英] Convert value from specific multidimensional array key into key in new array with original arrays as value

问题描述

基本上，我只是想知道是否有一种内置的方法，这种方法可能更快，例如使用array_map回调之类的方法:

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;
}

推荐答案

这应该对您有用:

只需将 NULL 作为第二个参数传递给 array_column() 可以获取完整的数组作为值，并使用 $ column 作为键的第三个参数.

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);

示例输入/输出:

$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);

输出:

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
        )

)

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