How can json be "converted"?

Question

PHP

Hello, there is a json like:
[{"PAN":"1234"},{"PAN":"123456789"}]
Need to get:
["1234","123456789"]
How can this be done in php?

Answer 1

$obj = json_decode($json);
$result=array();
foreach ($obj as $o) $result[]=$o["PAN"];
echo json_encode($result);

Answer 2

json_encode(
    array_column(
        json_decode('[{"PAN":"1234"},{"PAN":"123456789"}]', true),
        'PAN'
    )
);