I've got an array of cats objects:
$cats = Array (  => stdClass Object ( [id] => 15 ),  => stdClass Object ( [id] => 18 ),  => stdClass Object ( [id] => 23 ) )
and I want to extract an array of cats' IDs in 1 line (not a function nor a loop).
I was thinking about using
create_function but I don't know how to do it.
If you have PHP 5.5 or later, the best way is to use the built in function
But the son has to be an array or converted to an array