- var_dump: documentation ( source)
- json_decode: documentation ( source)
- array_column: documentation ( source)
<?php
$objs = json_decode('"obj":{"a":{"key":"a", "value":2, "index":1}, "b":{"key":"b", "value":3, "index":2}}', true);
var_dump($objs);
$objs = array_column($objs, null, "key");
$objs['a']['value'] = 5;
var_dump($objs);