Question

我有一组数据，我已经从JSON文件解析了我已经减少到出现次数。我现在需要对从大多数事件发生到最少发生的事件数进行排序。举个例子：

var myData = [{
        "datapoint1": "55",
        "datapoint2": "500",
        "datapoint3": "mydata@data.com",
        "datapoint4": 5656
    }, {
        "datapoint1": "55",
        "datapoint2": "404",
        "datapoint3": "mydata2@data.com",
        "datapoint4": 5656
    }, {
        "datapoint1": "55",
        "datapoint2": "502",
        "datapoint3": "mydata3@data.com",
        "datapoint4": 5656324
    }, {
        "datapoint1": "55",
        "datapoint2": "500",
        "datapoint3": "mydata33@data.com",
        "datapoint4": 5656554
    }
]

然后我采用了JSON并进行了解析，映射，然后减少到每个数据点2次出现的次数。为简洁起见，上面的虚拟数据重复5-6千次。

var dataParsed = JSON.parse(myData);
var mapDataPoint2 = dataParsed.map(function (data) {
    return data.datapoint2
});

var reduceDatapoint2 = mapDataPoint2.reduce(function (prev, cur) {
    prev[cur] = (prev[cur] || 0) + 1;
    return prev;
}, {});

console.log(reduceDatapoint2)

此时我可以将输出到控制台记录每次出现的次数。我现在需要能够从大多数到最小的分类。我试过.sort（）和似乎无法做任何事情，在控制台中没有错误。

任何帮助将不胜感激。

Answer 1

您可以使用reduceDatapoint2中的值进行排序：

myData.sort((a,b) => reduceDatapoint2[b.datapoint2] - reduceDatapoint2[a.datapoint2]);

样本

var myData = [{
    "datapoint1": "55",
    "datapoint2": "500",
    "datapoint3": "mydata@data.com",
    "datapoint4": 5656
  },
  {
    "datapoint1": "55",
    "datapoint2": "404",
    "datapoint3": "mydata2@data.com",
    "datapoint4": 5656
  },
  {
    "datapoint1": "55",
    "datapoint2": "502",
    "datapoint3": "mydata3@data.com",
    "datapoint4": 5656324
  },
  {
    "datapoint1": "55",
    "datapoint2": "500",
    "datapoint3": "mydata33@data.com",
    "datapoint4": 5656554
  }
]

var dataParsed = myData;
var mapDataPoint2 = dataParsed.map(function(data) {
  return data.datapoint2
});

var reduceDatapoint2 = mapDataPoint2.reduce(function(prev, cur) {
  prev[cur] = (prev[cur] || 0) + 1;
  return prev;
}, {});

console.log(reduceDatapoint2)

myData.sort((a, b) => reduceDatapoint2[b.datapoint2] - reduceDatapoint2[a.datapoint2]);
console.log(myData);

在JavaScript中减少数据后排序

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