如何格式化JSON對象數組（JavaScript）

Question

我在一個艱苦的要求中掙扎，我不知道該如何應對

我收到了一個數組，如下所示：

[{
    "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：將其轉換為以下格式的數組：

[{
    "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"]
}]

我發現lodash庫具有“ group by”功能，返回的結果非常接近，但不符合預期：

_.groupBy(array, 'student');

結果：

{
    "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"
    }]
}

任何建議都非常感謝。

Answer 1

我們可以使用數組的“ .reduce”功能並匯總結果，如下所示

 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

您需要將分組項目與其sport屬性進行映射，並使用分組信息構建新對象。

 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); 

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

Answer 3

結合使用Array.prototype.reduce（）與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);