Retrieve value from associative array-error

hello

i had stumbled on kinda simple problem but i can't get and idea what could be wrong:

        function zabbixGraphGetId($HostName, $Name,$zabbixData) {

            try {

                $api = new ZabbixApi(...$zabbixData);

            } catch (Exception $e) {
                // Exception in ZabbixApi catched
                echo $e->getMessage();
            }
            $GetGraphId = $api->graphGet(array(
                'output' => 'extend',
                'filter' => array('host' => $HostName),
                'search' => array('name' => $Name)
            ));
            $ReturnGraphId = $GetGraphId['0']->graphid;

            return $ReturnGraphId;
        }

Thats my function in symfony and i want to get from array $GetGraphId value of only graphid. Point is after i call this function i get this error: Warning: Attempt to read property "graphid" on array But if i'll return whole array($GetGraphId) i get this:

array:2 [
  0 => array:19 [
    "graphid" => "some id"
    "name" => "Network traffic on tun0"
    "width" => "900"
    "height" => "200"
    "yaxismin" => "0"
    "yaxismax" => "100"
    "templateid" => "0"
    "show_work_period" => "1"
    "show_triggers" => "1"
    "graphtype" => "0"
    "show_legend" => "1"
    "show_3d" => "0"
    "percent_left" => "0"
    "percent_right" => "0"
    "ymin_type" => "1"
    "ymax_type" => "0"
    "ymin_itemid" => "0"
    "ymax_itemid" => "0"
    "flags" => "4"
  ]

so there is graphid value yet i still cant get it, i would really appreciate any clues/ideas/solutions thanks!

The warning says it: Attempt to read property "graphid" on array. You cannot access graphid with object->property notation. Use this line instead:

$ReturnGraphId = $GetGraphId['0']['graphid'];