- Output for 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
- array ( 0 => array ( 0 => 'a', 1 => 'b', ), 1 => array ( 0 => 'c', ), )
<?php
$a = [
'a' => 0,
'b' => 0,
'c' => 1
];
$result = [];
foreach ($a as $result[$v][] => $v);
var_export($result);