Array mapping in PHP with keys

Question

Just for curiosity (I know it can be a single line foreach statement), is there some PHP array function (or a combination of many) that given an array like:

Array (
    [0] => stdClass Object (
        [id] => 12
        [name] => Lorem
        [email] => [email protected]
    )
    [1] => stdClass Object (
        [id] => 34
        [name] => Ipsum
        [email] => [email protected]
    )
)

And, given 'id' and 'name', produces something like:

Array (
    [12] => Lorem
    [34] => Ipsum
)

I use this pattern a lot, and I noticed that array_map is quite useless in this scenario cause you can't specify keys for returned array.

Answer 1

Just use array_reduce:

$obj1 = new stdClass;
$obj1 -> id = 12;
$obj1 -> name = 'Lorem';
$obj1 -> email = '[email protected]';

$obj2 = new stdClass;
$obj2 -> id = 34;
$obj2 -> name = 'Ipsum';
$obj2 -> email = '[email protected]';

$reduced = array_reduce(
    // input array
    array($obj1, $obj2),
    // fold function
    function(&$result, $item){ 
        // at each step, push name into $item->id position
        $result[$item->id] = $item->name;
        return $result;
    },
    // initial fold container [optional]
    array()
);

It's a one-liner out of comments ^^

Answer 2

I found I can do:

array_combine(array_map(function($o) { return $o->id; }, $objs), array_map(function($o) { return $o->name; }, $objs));

But it's ugly and requires two whole cycles on the same array.