循环遍历数组列表以计算对象

Question

我在用 javascript 计算这个数组中的对象数量时遇到了麻烦。 下面是我尝试用我的代码计算的对象数组。

       <script>

var arr = [
    {"gateways":["ccu1"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v3"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam"]},
    {"gateways":["v2","v3","v4","ccu2"],"manufacturer":["homematic","intertechno"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v2","ccu1","ccu2"],"manufacturer":["homematic"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["gw_none"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam"]},
    {"gateways":["v3","ccu2"],"manufacturer":["homematic","fs20","intertechno","elro","Eltako Enocean"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v3","v4"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_other"]},
    {"gateways":["v3","v4"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_other"]},
    {"gateways":["v2"],"manufacturer":["intertechno"],"ir":["ir_yes"],"ip":["ip_other"]}
];
var counter = [];
for(var i=0; i<arr.length; i++) {
    //console.log(arr[i]);

    for(var index in arr[i]) {
        console.log(index);

        if(counter[index] === undefined) {
            counter[index] = [];
        }

    }
}
console.log(counter);
    </script>

我希望在控制台记录“计数器”时将对象的数量推入空数组“计数器”，例如

网关
ccu2 42 v4 70 v2 95 v3 91 v4plus 32 ccu1 16 gw_none 10

IP
ip_cam 4 ip_other 10 ip_none 4

他们
ir_yes 13 ir_no 18

制造商
家庭式 24 fs20 59 国际技术 38 埃尔罗 63 家常 40 苏菲 11

我是编程新手，我尝试过一些类似这样的练习，但我被卡住了。我留下了将对象计数器放入空数组的代码。我试过但不能让它工作。我会很感激任何帮助，我希望我的任务是有意义的并且是可以理解的。

Answer 1

改变这个：

 if(counter[index] === undefined) {
        counter[index] = [];
 }

到这里：

 if(counter[index] === undefined) {
        counter[index] = [];
 }
 counter[index].push( arr[i][index] );  

Answer 2

希望此代码对您有所帮助。

var arr = [
    {"gateways":["ccu1"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v3"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam"]},
    {"gateways":["v2","v3","v4","ccu2"],"manufacturer":["homematic","intertechno"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v2","ccu1","ccu2"],"manufacturer":["homematic"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["gw_none"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_cam"]},
    {"gateways":["v3","ccu2"],"manufacturer":["homematic","fs20","intertechno","elro","Eltako Enocean"],"ir":["ir_yes"],"ip":["ip_cam","ip_other"]},
    {"gateways":["v3","v4"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_other"]},
    {"gateways":["v3","v4"],"manufacturer":["homematic"],"ir":["ir_no"],"ip":["ip_other"]},
    {"gateways":["v2"],"manufacturer":["intertechno"],"ir":["ir_yes"],"ip":["ip_other"]}
];


var types = Object.keys(arr[0]); //Returns ["gateways","manufacturer","ir","ip"]
var counter = {};
types.forEach(function(type){
  var values = [].concat.apply([], arr.map(function(d){ return d[type] })); // Find all values for each key like gateways
  //Count occurrence of each value
  var counts = {};  
  for(var i = 0; i< values.length; i++) {
    var num = values[i];
    counts[num] = counts[num] ? counts[num]+1 : 1;
  }
  counter[type] = counts;
});

alert(JSON.stringify(counter));

获得的输出：

{
    "gateways": {
        "ccu1": 2,
        "v3": 5,
        "v2": 3,
        "v4": 3,
        "ccu2": 3,
        "gw_none": 1
    },
    "manufacturer": {
        "homematic": 8,
        "intertechno": 3,
        "fs20": 1,
        "elro": 1,
        "Eltako Enocean": 1
    },
    "ir": {
        "ir_no": 5,
        "ir_yes": 4
    },
    "ip": {
        "ip_cam": 6,
        "ip_other": 7
    }
}

Answer 3

谢谢大家，但我坐下来认为我得到了我所缺少的东西；

        //first we initialised counter 
    var counter = [];

    //we then loop over the big array
    for(var i=0; i<arr.length; i++) {

        //we save then the single objects
        var obj = arr[i];

        // We then evaluate Object -> looping and count on each entry
        for(var key in obj) {

        //check whether there is already an entry for the respective
        //index (gateways, Manufacturer etc)
            if(counter[key] === undefined) {
                counter[key] = [];
            }


            //Save the individual array of Object entries
            var arr2 = obj[key];

            //Looping and counting the array
            for(var k=0; k<arr2.length; k++) {                    
                var entry = arr2[k];

                //Check whether there is already a counter for that
                //item
                if(counter[key][entry] === undefined) {
                    counter[key][entry] = 1;
                } else {
                    counter[key][entry]++;
                }
            }
        }
    }
    console.log(counter);