在对象数组中找到最常见的项目

Question

我需要帮助来创建一个函数来使用 vanilla 或例如 lodash 来循环对象数组并获取数组中出现次数最多的对象，这是我的对象：[{"s":97,"p":75},{"s":99,"p":93},{"s":97,"p":75},{"s":97,"p":76},{"s":97,"p":75},{"s":97,"p":75},{"s":97,"p":74},{"s":86,"p":80},{"s":97,"p":73},{"s":97,"p":71},{"s":97,"p":71}]结果应该是：{"s":97,"p":75}提前致谢

Answer 1

您可以通过Array.prototype.reduce()构建一个复杂的对象来遍历源数组，以跟踪每个对象的出现、到目前为止最常看到的对象以及实际看到最常见对象的次数。

所以，一旦一些数组项超过maxCount它就变成了mostOften。

这样你就可以只通过所有项目来找到获胜者：

const src = [{"s":97,"p":75},{"s":99,"p":93},{"s":97,"p":75},{"s":97,"p":76},{"s":97,"p":75},{"s":97,"p":75},{"s":97,"p":74},{"s":86,"p":80},{"s":97,"p":73},{"s":97,"p":71},{"s":97,"p":71}],

      {mostOften} = src.reduce((r,{s,p}) => {

        const hash = s+'\ud8ff'+p

        r.hashCount[hash] = (r.hashCount[hash]||0) + 1

        r.hashCount[hash] > r.maxCount &&

        (r.mostOften = {s,p}, r.maxCount = r.hashCount[hash])

        return r

      }, {hashCount: {}, mostOften: null, maxCount: 0})

      

console.log(mostOften)      

      

Answer 2

这里重要的是为您认为“相同”的对象提供可靠的密钥。我会建议JSON.stringify由两个属性组成的数组：

let data = [{"s":97,"p":75},{"s":99,"p":93},{"s":97,"p":75},{"s":97,"p":76},{"s":97,"p":75},{"s":97,"p":75},{"s":97,"p":74},{"s":86,"p":80},{"s":97,"p":73},{"s":97,"p":71},{"s":97,"p":71}];

let keys = Object.fromEntries(data.map(o => [ JSON.stringify([o.s, o.p, "s" in o, "p" in o]), o ]));

let counter = {};

for (let key in keys) counter[key] = (counter[key] || 0) + 1;

let bestKey = Object.entries(counter).reduce((max, [key, count]) =>

    count > max[1] ? [key, count] : max, ["", 0])[0];

    

let result = keys[bestKey];

console.log(result);

即使s或p是带有任何外来字符的字符串，或布尔值，或null, 或原语（的数组）数组，......这仍然有效。

Answer 3

let arr = [{"s":97,"p":75},{"s":99,"p":93},{"s":97,"p":75},{"s":97,"p":76},{"s":97,"p":75},{"s":97,"p":75},{"s":97,"p":74},{"s":86,"p":80},{"s":97,"p":73},{"s":97,"p":71},{"s":97,"p":71}]

let obj = {};

let maxCount = 0;

let result;

arr.forEach(e => {

  let key = `s:${e.s}:p:${e.p}`;

  obj[key] = obj[key] || 0;

  obj[key] += 1;

  if(obj[key] > maxCount){

    maxCount = obj[key];

    result = e;

  }

});

console.log(result);