如何按特定值获取数组索引号

I have an array

Its a json data.

"score":[
    {
        "userId":"5",
        "playtime":"1396369254",
        "score":"25"
    },
    {
        "userId":"3",
        "playtime":"1396369246",
        "score":"2"
    },
    {
        "userId":"1",
        "playtime":"1396369056",
        "score":"12"
    },
    {
        "userId":"2",
        "playtime":"1396369240",
        "score":"100"
    }
],

I want to print array index number which userId value is 1.

Use a foreach as such:

foreach($array as $key=>$value) {
    if($value['userId'] == 1) {
        print $key;
        break;
    }
}