Question

我正在努力应对一个严格的要求，我不知道如何应对

我收到了一个数组如下：

[{
    "student": "21_A_1",
    "sport": "badminton"
}, {
    "student": "21_C_1",
    "sport": "badminton"
}, {
    "student": "21_A_2",
    "sport": "badminton"
}, {
    "student": "21_B_1",
    "sport": "football"
}, {
    "student": "21_A_2",
    "sport": "football"
}]

要求：将其转换为格式为：

的数组

[{
    "student": "21_A_1",
    "sport": ["badminton"]
}, {
    "student": "21_C_1",
    "sport": ["badminton"]
}, {
    "student": "21_A_2",
    "sport": ["badminton","football"]
}, {
    "student": "21_B_1",
    "sport": ["football"]
}]

我发现lodash库有一个功能＆＃34; group by＆＃34;返回非常封闭的结果，但不是期望：

_.groupBy(array, 'student');

结果：

{
    "21_A_1": [{
        "student": "21_A_1",
        "sport": "badminton"
    }],
    "21_C_1": [{
        "student": "21_C_1",
        "sport": "badminton"
    }],
    "21_A_2": [{
        "student": "21_A_2",
        "sport": "badminton"
    }, {
        "student": "21_A_2",
        "sport": "football"
    }],
    "21_B_1": [{
        "student": "21_B_1",
        "sport": "football"
    }]
}

非常感谢任何建议。

Answer 1

我们可以使用数组的'.reduce'函数和聚合结果如下

var test = [{
    "student": "21_A_1",
    "sport": "badminton"
}, {
    "student": "21_C_1",
    "sport": "badminton"
}, {
    "student": "21_A_2",
    "sport": "badminton"
}, {
    "student": "21_B_1",
    "sport": "football"
}, {
    "student": "21_A_2",
    "sport": "football"
}]
const result = test.reduce((res,x)=>{
   res[x.student] = res[x.student] || { student:x.student,sport:[]}
   res[x.student].sport.push(x.sport)
   return res;
},{})

console.log(result)

Answer 2

您需要使用sport属性映射分组的项目，并使用分组信息构建新对象。

var array = [{ student: "21_A_1", sport: "badminton" }, { student: "21_C_1", sport: "badminton" }, { student: "21_A_2", sport: "badminton" }, { student: "21_B_1", sport: "football" }, { student: "21_A_2", sport: "football" }],
    grouped = _(array)
        .groupBy('student')
        .map((group, student) => ({ student, sport: _.map(group, 'sport') }))
        .value();

console.log(grouped);

.as-console-wrapper { max-height: 100% !important; top: 0; }

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.15.0/lodash.min.js"></script>

Answer 3

使用Array.prototype.reduce()结合Object.values()：

const data = [{"student": "21_A_1","sport": "badminton"}, {"student": "21_C_1","sport": "badminton"}, {"student": "21_A_2","sport": "badminton"}, {"student": "21_B_1","sport": "football"}, {"student": "21_A_2","sport": "football"}];
const result = Object.values(
  data.reduce((a, c) => ((a[c.student] = a[c.student] || {student: c.student, sport: []}).sport.push(c.sport), a), {})
);

console.log(result);

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