在数组中查找唯一元素，并找到重复元素的字段总和（比如标记）

作者: 咿呀哟
发布时间: 2024-12-17 07:45:16 (2月前)
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青阳 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 您可以将学生数组分组到卷号上，并在对象累加器中添加相同卷号的标记。运用 <code> array#values() </code> 获取与卷号对应的所有值。 </p> <P> </p> <div class =“snippet”data-lang =“js”data-hide =“false”data-console =“true”data-babel =“false”> <div class =“snippet-code”> <pre class="snippet-code-js lang-js prettyprint-override"> <code> let studentsList = [{ name:'A', rollNo:1, mark:10 }, { name:'B', rollNo:2, mark:30 }, { name:'C', rollNo:3, mark:40 }, { name:'A', rollNo:1, mark:50 } ], uniqueStudents = Object.values(studentsList.reduce((r,{name, rollNo, mark}) => { r[rollNo] = r[rollNo] || {name, rollNo, total : 0}; r[rollNo].total += mark; return r; },{})); console.log(uniqueStudents); </code> </pre> </DIV> </DIV> <P> </p> </DIV>

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尼拉。 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 您可以将此功能用于管道： </p> <pre> <code> value.reduce((acc, ele) => { const existingStudent = acc.find(x => x.name === ele.name); if(!existingStudent) return acc.concat(ele); return (existingStudent.mark += ele.mark, acc); },[]) </code> </pre> <P> 测试它： </p> <P> </p> <div class =“snippet”data-lang =“js”data-hide =“false”data-console =“true”data-babel =“false”> <div class =“snippet-code”> <pre class="snippet-code-js lang-js prettyprint-override"> <code> var studentsList=[{name:"A",rollNo:1,mark:10},{name:"B",rollNo:2,mark:30},{name:"C",rollNo:3,mark:40},{name:"A",rollNo:1,mark:50}]; const resp = studentsList.reduce((acc, ele) => { const existingStudent = acc.find(x => x.name === ele.name); if(!existingStudent) return acc.concat(ele); return (existingStudent.mark += ele.mark, acc); },[]) console.log(resp); </code> </pre> </DIV> </DIV> <P> </p> </DIV>

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⑩Ⅵ嵗Ｄ夨憶 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 如何累积值的示例。 </p> <P> </p> <div class =“snippet”data-lang =“js”data-hide =“false”data-console =“true”data-babel =“false”> <div class =“snippet-code”> <pre class="snippet-code-js lang-js prettyprint-override"> <code> let studentsList = [ { name: 'A', rollNo: 1, mark: 10 }, { name: 'B', rollNo: 2, mark: 30 }, { name: 'C', rollNo: 3, mark: 40 }, { name: 'A', rollNo: 1, mark: 50 } ]; const byName = {}; for (var student of studentsList) { if (student.name in byName) { byName[student.name].mark += student.mark; } else { byName[student.name] = { ...student }; } } console.log(Object.values(byName)); </code> </pre> </DIV> </DIV> <P> </p> </DIV>

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3#
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梦中会飞的鱼 | 2019-08-31 10-32

<div class =“post-text”itemprop =“text”> <P> 如果你需要一个名称和标记的结果数组（重复的总和），那么你可以在lodash中使用一种非常简洁的方式（因为你标记了lodash）。 <a href="https://lodash.com/docs/4.17.11#groupBy" rel="nofollow noreferrer"> _。通过...分组 </A> 将始终按其唯一参数对其进行分组，并将所有重复项与该参数组合在一个数组中。 </p> <OL> <LI> 首先，将其分组 <code> name </code> 运用 <a href="https://lodash.com/docs/4.17.11#groupBy" rel="nofollow noreferrer"> _。通过...分组 </A> </LI> <LI> 然后映射（ <a href="https://lodash.com/docs/4.17.11#map" rel="nofollow noreferrer"> <EM> 。地图 </EM> </A> ）每组并计算标记总和 <a href="https://lodash.com/docs/4.17.11#sumBy" rel="nofollow noreferrer"> .sumBy </A> </LI> </醇> <P> 这是一个工作示例： </p> <P> </p> <div class =“snippet”data-lang =“js”data-hide =“false”data-console =“true”data-babel =“false”> <div class =“snippet-code”> <pre class="snippet-code-js lang-js prettyprint-override"> <code> let input = [{"name":"A","rollNo":1,"mark":10},{"name":"B","rollNo":2,"mark":30},{"name":"C","rollNo":3,"mark":40},{"name":"A","rollNo":1,"mark":50}], res = _(input) .groupBy('name') .map((g, name) => ({name, mark: _.sumBy(g, 'mark')})) .value(); console.log(res); </code> </pre> <pre class="snippet-code-html lang-html prettyprint-override"> <code> <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script> </code> </pre> </DIV> </DIV> <P> </p> </DIV>

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