比较JSON中的信息，在列表中返回前几个结果

Question

给定以下JSON：

[
    {
        "group": "satellite-1",
        "data": [
            {
                "label": "feed1-1_TargetA",
                "data": [
                    {"timeRange": ["11:40:00 AM", "11:40:20 AM"], val: "TargetA"},
                    {"timeRange": ["11:40:20 AM", "11:40:40 AM"], val: "TargetA"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetA"},
                ]
            },
            {
                "label": "feed1-1_TargetB",
                "data": [
                    {"timeRange": ["11:40:40 AM", "11:41:00 AM"], val: "TargetB"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetB"}
                ]
            },
            {
                "label": "feed1-1_TargetC",
                "data": [
                    {"timeRange": ["11:40:40 AM", "11:41:00 AM"], val: "TargetC"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetC"},
                ]
            },
            {
                "label": "feed1-1_TargetD",
                "data": [
                    {"timeRange": ["11:40:40 AM", "11:41:00 AM"], val: "TargetD"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetD"},
                ]
            },
            {
                "label": "feed1-2_TargetB",
                "data": [
                    {"timeRange": ["11:40:20 AM", "11:40:40 AM"], val: "TargetB"}
                ]
            }

        ]
    },
    {
        "group": "satellite-2",
        "data": [
            {
                "label": "feed2-1_TargetA",
                "data": [
                    {"timeRange": ["11:40:20 AM", "11:40:40 AM"], val: "TargetA"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetA"},
                ]
            },
            {
                "label": "feed2-1_TargetB",
                "data": [
                    {"timeRange": ["11:40:40 AM", "11:41:00 AM"], val: "TargetB"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetB"}
                ]
            },
            {
                "label": "feed2-1_TargetC",
                "data": [
                    {"timeRange": ["11:40:40 AM", "11:41:00 AM"], val: "TargetC"},
                    {"timeRange": ["11:41:00 AM", "11:41:20 AM"], val: "TargetC"},
                ]
            },
            {
                "label": "feed2-2_TargetB",
                "data": [
                    {"timeRange": ["11:40:20 AM", "11:40:40 AM"], val: "TargetB"}
                ]
            }

        ]
    }
]

我正在尝试比较哪些提要的目标数量最多。

到目前为止，我已经解决了这个问题，因为我可以遍历JSON，并通过比较每个提要的长度返回“最有观察力的提要”。

/*
 * Compare length of each sensor block in data to determine which sensor
 * is most observant
 */
var getMostObservantFeeds = function(entry){
    var bestFeed = null;


    for(var d of entry.data){
        if (bestFeed == null){
            bestFeed = d;
        }
        if (bestFeed.data.length < d.data.length){
            bestFeed = d;
        }
    }

    bestFeed = bestFeed || {};

    return bestFeed.label
    ])
};

var getMostObservantFeed = function(data_JSON){
    return data_JSON.map(x => getMostObservantFeeds(x));
};

但是，当一个提要和另一个提要具有相同的长度时，我不能让它工作。

如果两个提要看到相同数量的目标(这是看到的最大数量)，我该如何返回最佳提要的列表？(即satellite2: feed2-1_TargetA，feed2-1_TargetB，feed2-1_TargetC)

Answer 1

记录最大值并比较每次的结果如何？也许只是将标签存储在数组中，因为这就是您要返回的所有内容？

var getMostObservantFeed = function(entry){
    var bestLabels = [];
    var max = 0;

    for(var d of entry.data){
        if (d.data.length >= max){
            max = d.data.length;
            bestLabels.push(d.label);
        }
    }

    return bestLabels;
};

Answer 2

我建议您使用第二个条件来检查bestFeed.data和d.data是否具有相同的长度。在for循环中的第二个if语句后添加类似以下内容：

else if(bestFeed.data.length === d.data.length){  
    //do further checking here
}

在这个条件中，您可以再次比较bestfeed和d (可能是timerange属性)。

我还建议您使用d之外的其他工具，例如i或item