- array_map: documentation ( source)
- implode: documentation ( source)
<?php
$input = array("name 1" =>
array(
'tag_name' => 'google'
),
"name 2" => array(
'tag_name' => 'technology'
)
);
echo implode(', ', array_map(function ($entry) {
return $entry['tag_name'];
}, $input));