使用javascript从JSON获取两个顶部4键和值的不同数组

Question

假设我有一个JSON对象。

var JSONObj = "skills":[
            {
                "skill": "HTML",
                "rate": "4"
            },
            {
                "skill": "JS",
                "rate": "5"
            },
            {
                "skill": "jQuery",
                "rate": "8"
            },
            {
                "skill": "Angular 2",
                "rate": "1"
            },
            {
                "skill": "XML",
                "rate": "3"
            },
            {
                "skill": "CSS",
                "rate": "10"
            }
        ]

我想根据TopRates和TopSkills在Javascript中的速率为它们生成两个不同的数组。例如，var TopSkills = ["CSS", "jQuery", "JS", "HTML"]; var TopRates = [10, 8, 5, 4]

Answer 1

您可以使用reduce()返回技能和比率数组，然后使用slice()返回前4。

​

var JSONObj = {
  "skills": [{
    "skill": "HTML",
    "rate": "4"
  }, {
    "skill": "JS",
    "rate": "5"
  }, {
    "skill": "jQuery",
    "rate": "8"
  }, {
    "skill": "Angular 2",
    "rate": "1"
  }, {
    "skill": "XML",
    "rate": "3"
  }, {
    "skill": "CSS",
    "rate": "10"
  }]
}

var r = JSONObj.skills.sort((a, b) => b.rate - a.rate).reduce(function(r, e) {
  r.skills = (r.skills || []).concat(e.skill);
  r.rates = (r.rates || []).concat(e.rate);
  return r;
}, {})

var TopSkills = r.skills.slice(0, 4);
var TopRates = r.rates.slice(0, 4);
console.log(TopSkills)
console.log(TopRates)

​

Answer 2

您可以先按比率对数组进行排序，然后用技巧和速率进行映射：

var sortedBySkill = JSONObj.skills.sort(function(a, b) {
    return b.rate - a.rate;
});

console.log(sortedBySkill.map(function(a) {
    return a.skill;
}).slice(0,4));

console.log(sortedBySkill.map(function(a) {
    return a.rate;
}).slice(0,4));

这是小提琴。希望能帮上忙。

Answer 3

甚至可以很容易地使用forEach

var topSkills = [];
var topRates = [];
JSONObj.skills.sort((a, b) => b.rate - a.rate).forEach(item => {
  topSkills.push(item.skill);
  topRates.push(item.rate);
});