is there a way to have array_column() keep the $input array key? [duplicate]

Question

Suppose I have an array of records, keyed by some ID, and I use the array_column() function to extract one piece of data from each record.

$records = array(
    1234 => array(
        'first_name' => 'John',
        'last_name' => 'Doe',
    ),
    4567 => array(
        'first_name' => 'Sally',
        'last_name' => 'Smith',
    ),
);

The result from array_column($input, 'first_name') is a numerically indexed array (with new keys 0, 1, ...). Is there a way of keeping the keys from the input array?

$newArray = array_combine(array_keys($records), array_column($records, 'first_name')); — Mark Baker
– Mark Baker, Commented Jun 20, 2017 at 13:55

user11927553 · Accepted Answer · 2019-08-14 16:20:45Z

1

array_map(function ($r) { return $r['first_name']; }, $records)

will do (for your precise case).

It is more or less equivalent to this (PHP 7+):

(function () use ($records) {
    $result = [];
    foreach ($records as $key => $r) {
        $result[$key] = $r['first_name'];
    }
    return $result;
)()

edited Aug 14, 2019 at 16:20

answered Aug 14, 2019 at 13:20

user11927553

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Comments

Giso Stallenberg · Accepted Answer · 2017-06-20 13:58:59Z

0

When the id would also be available in the data array's you could use the third argument of array_column.

For example: array_column($records, 'first_name', 'id');

answered Jun 20, 2017 at 13:58

Giso Stallenberg

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1 Comment

joachim Over a year ago

Sorry, I should have made it clear - the desired data isn't available in the arrays, only as the key.

pbarney · Accepted Answer · 2021-12-10 23:28:52Z

0

Here's a simple function I often use:

function array_column_with_keys(array $array, string $column): array {
    return array_combine(
        array_keys($array), 
        array_column($array, $column));
}

So using your example array,

var_export(array_column_with_keys($records, 'first_name'));

will return:

array (
  1234 => 'John',
  4567 => 'Sally',
)

answered Dec 10, 2021 at 23:28

pbarney

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