- array_reduce: documentation ( source)
- array_merge: documentation ( source)
- array_values: documentation ( source)
- implode: documentation ( source)
<?php
$array = [
'name' => ['Some message to display1'],
'test' => ['Some message to display2'],
'kudos' => ['Some message to display3']
];
echo implode(', ', array_merge(...array_values($array)));
echo "\n---\n";
echo array_reduce($array, function($carry, $item) {return $carry .= ($carry ? ', ' : '') . $item[0]; }, '');