- var_dump: documentation ( source)
- array_key_first: documentation ( source)
<?php
$a = [
['a'=>'bla'],
['b'=>'test'],
['a'=>'foo'],
['c'=>'bar']
];
$b = [];
foreach ($a as $v) {
$k = array_key_first($v);
$b[$k][] = $v[$k];
}
var_dump($b);