use of $obj-> in php code example

Example 1: php create object

$x = (object) [
    'a' => 'test',
    'b' => 'test2',
    'c' => 'test3'
];
var_dump($x);

/*
object(stdClass)#1 (3) {
  ["a"]=>
  string(4) "test"
  ["b"]=>
  string(5) "test2"
  ["c"]=>
  string(5) "test3"
}
*/

Example 2: php dar echo em um stdClass

<?php
$obj = (object) array('1' => 'foo');
var_dump(isset($obj->{'1'})); // outputs 'bool(true)' as of PHP 7.2.0; 'bool(false)' previously
var_dump(key($obj)); // outputs 'string(1) "1"' as of PHP 7.2.0; 'int(1)' previously
?>