- var_dump: documentation ( source)
- json_decode: documentation ( source)
- array_keys: documentation ( source)
- json_encode: documentation ( source)
<?php
$Data = json_decode(json_encode([4=>4,5=>5,6=>6]));
var_dump($Data);
$Data = (array)$Data;
var_dump(array_keys($Data));
//var_dump($Data,$Data[4],$Data['4']);
var_dump($Data[json_decode(json_encode("4"))]);