PHP - obtaining sub-array in a single expression

Question

Is there a way to get, in a single expression, a sub-array from an array, giving specific keys from the original array?

By example:

$a = array('a' => 1, 'b' => 2, 'c' = 4, 'd' => 'clorch')
$b = doesthisfunctionexist($a, 'a', 'c')
//$b containing array('a' => 1, 'c' => 4)

I know I can code that function, but I'm asking if such a similar native function exists.

Do you mean array_key_exists()? For example: true === array_key_exists('a', ['a' => 1]);. It only works for one key at a time though. ie2.php.net/array_key_exists — Darragh Enright
– Darragh Enright, Commented Apr 15, 2014 at 15:00
array_key_exists is not what I expect. from the name one can infer the return value is boolean. from the doc one can confirm it. see what does $b contain in the third expression - that's what I'm looking for. — Luis Masuelli
– Luis Masuelli, Commented Apr 15, 2014 at 15:02

nni6 · Accepted Answer · 2014-04-15 15:07:28Z

6

$a = array(
  "a" => 1,
  "b" => 2,
  "c" => 4,
  "d" => "clorch",
);
$b = array_intersect_key($a, array_flip(array('a', 'c')));

answered Apr 15, 2014 at 15:07

nni6

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1 Comment

Luis Masuelli Over a year ago

I was thinking about this alternative. Seems it's the only one I could figure using native functions (perhaps replacing array_flip with array_fill, but the idea was the same).

mamdouh alramadan · Accepted Answer · 2014-04-15 15:02:33Z

1

I am not aware of such a function but, you can do the following:

function array_pick($picks, $array)
    {
     $temp = array();
        foreach($array as $key => $value)
        {
            if(in_array($key, $picks))
            {
                $temp[$key] = $value;
            }
        }
     return $temp;
    }

try it like so:

 $a = array('a' => 1, 'b' => 2, 'c' =>4, 'd' => 'clorch');
    $b = array('b','c');
    $z = array_pick($b,$a);
    var_dump($z);

output:

array(2) {
  ["b"]=>
  int(2)
  ["c"]=>
  int(4)
}

answered Apr 15, 2014 at 15:02

mamdouh alramadan

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Comments

user1180790 · Accepted Answer · 2014-04-15 15:08:55Z

1

$a = array('a' => 1, 'b' => 2, 'c' => 4, 'd' => 'clorch');
$b = array_intersect_key($a, array_flip(array('a', 'c')));

answered Apr 15, 2014 at 15:08

user1180790

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