Question

我正在努力获得＆＃34;当前＆＃34;的价值。从这个JSON数据。我需要在一行中没有任何循环。有什么建议吗？

     var data=[

     {"id":728,"acc":50,"date":"03-10-2017 05:45"},
     {"id":727,"acc":30,"date":"03-09-2017 21:00"},
     {"id":726,"acc":50,"date":"03-09-2017 05:45"},
     {"id":725,"acc":30,"date":"03-08-2017 21:00"},
     {"id":724,"acc":50,"date":"03-08-2017 05:45"},
     {"id":723,"acc":30,"date":"03-07-2017 21:15"},
     {"id":722,"acc":50,"date":"03-07-2017 05:45"},
     {"id":721,"acc":30,"date":"03-06-2017 21:00"},
     {"id":720,"acc":50,"date":"03-06-2017 05:45"},
     {"id":719,"acc":30,"date":"03-03-2017 21:00"},
     {"id":718,"acc":50,"date":"03-03-2017 05:45"},
     {"id":717,"acc":30,"date":"03-02-2017 21:00"},
     {"id":716,"acc":50,"date":"03-02-2017 05:45"},
     {"id":715,"acc":30,"date":"03-01-2017 21:00"},
     {"id":714,"acc":50,"date":"03-01-2017 05:45"},
     {"id":713,"acc":30,"date":"02-28-2017 21:00"},

     [
      {"current":"03-10-2017 05:45"}
     ]

     ];

     var mval = data[0].current;
     alert(mval);

     //alert(data[1].current);

谢谢！

Answer 1

安全解决方案只会找到属性为current的数组

data.find(v => v.length && v[0].current)[0].current;

Answer 2

data[data.length - 1][0].current

Answer 3

如果数据始终相同，则这是您的单行

var mval = data[data.length - 1][0].current;

如果数据可能发生变化，你可以循环通过数组并找到像这样的内部数组

var myVal;
    for(obj in data) {
        if(data[obj].constructor === Array) {
            myVal = data[obj];
        }
    }

    alert(myVal[0].current);

window.onload = function () {
    var data = [

        { "id": 728, "acc": 50, "date": "03-10-2017 05:45" },
        { "id": 727, "acc": 30, "date": "03-09-2017 21:00" },
        { "id": 726, "acc": 50, "date": "03-09-2017 05:45" },
        { "id": 725, "acc": 30, "date": "03-08-2017 21:00" },
        { "id": 724, "acc": 50, "date": "03-08-2017 05:45" },
        { "id": 723, "acc": 30, "date": "03-07-2017 21:15" },
        { "id": 722, "acc": 50, "date": "03-07-2017 05:45" },
        { "id": 721, "acc": 30, "date": "03-06-2017 21:00" },
        { "id": 720, "acc": 50, "date": "03-06-2017 05:45" },
        { "id": 719, "acc": 30, "date": "03-03-2017 21:00" },
        { "id": 718, "acc": 50, "date": "03-03-2017 05:45" },
        { "id": 717, "acc": 30, "date": "03-02-2017 21:00" },
        { "id": 716, "acc": 50, "date": "03-02-2017 05:45" },
        { "id": 715, "acc": 30, "date": "03-01-2017 21:00" },
        { "id": 714, "acc": 50, "date": "03-01-2017 05:45" },
        { "id": 713, "acc": 30, "date": "02-28-2017 21:00" },

        [
            { "current": "03-10-2017 05:45" }
        ]

    ];

    var myVal;
    for(obj in data) {
        if(data[obj].constructor === Array) {
            myVal = data[obj];
        }
    }

    alert(myVal[0].current);

}

Answer 4

假设数据中唯一的“数组”类型对象是包含具有“当前”键的对象的对象，您可以使用：

var current = data.filter(function(x){ return  Object.prototype.toString.call( x ) === '[object Array]';} )[0][0].current;

查看Check if object is array?

Answer 5

假设current可以在数组中的任何位置，您需要迭代才能找到它：

var current;
data.some(function(e) {
  if(e[0] && e[0].current) {  //make sure it's an array with an object key "current"
    current = e[0].current;
  }
});

＆＃13;

var data=[

     {"id":728,"acc":50,"date":"03-10-2017 05:45"},
     {"id":727,"acc":30,"date":"03-09-2017 21:00"},
     {"id":726,"acc":50,"date":"03-09-2017 05:45"},
     {"id":725,"acc":30,"date":"03-08-2017 21:00"},
     {"id":724,"acc":50,"date":"03-08-2017 05:45"},
     {"id":723,"acc":30,"date":"03-07-2017 21:15"},
     {"id":722,"acc":50,"date":"03-07-2017 05:45"},
     {"id":721,"acc":30,"date":"03-06-2017 21:00"},
     {"id":720,"acc":50,"date":"03-06-2017 05:45"},
     {"id":719,"acc":30,"date":"03-03-2017 21:00"},
     {"id":718,"acc":50,"date":"03-03-2017 05:45"},
     {"id":717,"acc":30,"date":"03-02-2017 21:00"},
     {"id":716,"acc":50,"date":"03-02-2017 05:45"},
     {"id":715,"acc":30,"date":"03-01-2017 21:00"},
     {"id":714,"acc":50,"date":"03-01-2017 05:45"},
     {"id":713,"acc":30,"date":"02-28-2017 21:00"},

     [
      {"current":"03-10-2017 05:45"}
     ]

     ];

var current;
data.some(function(e) {
  if(e[0] && e[0].current) {
    current = e[0].current;
  }
});

console.log(current);

＆＃13;

从JSON数据中获取值

5 个答案: