Return single column from a multi-dimensional array

Question

I'm a novice at PHP and I need a quick solution to the following problem but can't seem to come up with one:

I have a multi-dimensional array like so

Array
(
    [0] => Array
        (
            [blogTags_id] => 1
            [tag_name] => google
            [inserted_on] => 2013-05-22 09:51:34
            [inserted_by] => 2
        )

    [1] => Array
        (
            [blogTags_id] => 2
            [tag_name] => technology
            [inserted_on] => 2013-05-22 09:51:34
            [inserted_by] => 2
        )
)

I want to use the implode() to somehow return a comma-separated string containing values of tag_name key like so.

google, technology

Is it possible to achieve this effect with the said function? If not then please suggest an alternate solution.

Answer 1

Quite simple:

$input = array(
  array(
    'tag_name' => 'google'
  ),
  array(
    'tag_name' => 'technology'
  )
);

echo implode(', ', array_map(function ($entry) {
  return $entry['tag_name'];
}, $input));

http://3v4l.org/ltBZ0

---

and new in php v5.5.0, array_column:

echo implode(', ', array_column($input, 'tag_name'));