PHP Json解码对象存在

Question

我如何从存在“ gameid”且值为“ 730”的玩家那里获取所有“ steamid”？它显示：
NOTICE未定义属性：第31行的stdClass :: $ gameid，因为在每个元素中都不存在“ gameid”

码：

$players = json_decode(file_get_contents("test.json"));
foreach($players->response->Players as $mydata)
{
if($players->gameid == "730"){
echo $mydata->steamid . "\n";
}

}   

我的json：

{
    "response": {
        "players": [
            {
                "steamid": "76561198273176399",
                "loccountrycode": "US"
            },
            {
                "steamid": "76561198386141115",
                "gameid": "730",
                "loccountrycode": "DE"
            },
            {
                "steamid": "76561198019025166",
                "gameid": "730",
                "loccountrycode": "RU"
            },
            {
                "steamid": "76561198010529217",
                "loccountrycode": "DK"
            }
        ]

    }
}

非常感谢。最诚挚的问候。

Answer 1

更改

$players->response->Players
if($players->gameid == "730"){

至

$players->response->players // small letter "p"
if($mydata->gameid == "730"){

和...一样 $mydata->steamid

由于并非每个玩家都有一个，gameid因此最好也检查一下：

if( isset($mydata->gameid) && $mydata->gameid === '730' ) // or check on empty if the "gameid" can be set but also can be empty