logo标签列表

按百分比排名用户，使用map/filter/reduce

javascript
3
我希望基于用户的分数百分比显示所有用户的详细信息并为他们分配排名。这里我已经获取了所有的详细信息。如何排序和打印用户，请看下方代码：
Tom has scored marks in Science - 80 Maths - 89 English - 91 and secured 86.67 % and his rank is 1.

同样，students对象中的每个用户也是如此。
var students = [{
  name: "John",
  age: 20,
  id: 1,
  marks: {
    science: 80,
    maths: 90,
    english: 67
  }
}, {
  name: "Jack",
  age: 22,
  id: 3,
  marks: {
    science: 56,
    maths: 91,
    english: 81
  }
}, {
  name: "Robert",
  age: 23,
  id: 2,
  marks: {
    science: 75,
    maths: 79,
    english: 87
  }
}, {
  name: "Tom",
  age: 20,
  id: 4,
  marks: {
    science: 80,
    maths: 89,
    english: 91
  }
}];


var inDetail = getPercentageAndRank(students);

function getPercentageAndRank(students) {

  var details = students.map(function(getMarks) {
    console.log(((getMarks.marks.english + getMarks.marks.maths + getMarks.marks.science) / 3));
    return {
      name: getMarks.name,
      science: getMarks.marks.science,
      maths: getMarks.marks.maths,
      english: getMarks.marks.english,
      percentage: ((getMarks.marks.english + getMarks.marks.maths + getMarks.marks.science) / 3)
    };
  })

  return details.map(function(gg) {
    return [
      gg.name,
      "has scored marks in Science -",
      gg.science,
      "Maths -",
      gg.maths,
      "English -",
      gg.english,
      "and secured", (gg.percentage).toFixed(2),
      "%."
    ].join(' ');

  });
}

输出：

["John has scored marks in Science - 80 Maths - 90 English - 67 and secured 79.00 %.",
    "Jack has scored marks in Science - 56 Maths - 91 English - 81 and secured 76.00 %.",
    "Robert has scored marks in Science - 75 Maths - 79 English - 87 and secured 80.33 %.",
    "Tom has scored marks in Science - 80 Maths - 89 English - 91 and secured 86.67 %."]

我得到的输出结果与之前所说的不符。如何获得上述结果。

请注意，这段话中的 HTML 标签已被保留。
1
你应该自己完成作业。 - sahbeewah
其实这不是一道作业题，而是我的项目需求，并且我对问题进行了修改。 - disciple
你不需要使用reduce，因为你之前类似问题的答案已经给出了 - http://stackoverflow.com/questions/32354201/how-to-combine-two-arrays-using-map-filter-reduce - 因为这次你想要的输出是一个数组...但你需要使用sort。 - Jaromanda X
1个回答
2

您需要添加：

.sort(function(a, b) {
    return b.percentage - a.percentage;
  });

请检查这个解决方案。

var students = [{
  name: "John",
  age: 20,
  id: 1,
  marks: {
    science: 80,
    maths: 90,
    english: 67
  }
}, {
  name: "Jack",
  age: 22,
  id: 3,
  marks: {
    science: 56,
    maths: 91,
    english: 81
  }
}, {
  name: "Robert",
  age: 23,
  id: 2,
  marks: {
    science: 75,
    maths: 79,
    english: 87
  }
}, {
  name: "Tom",
  age: 20,
  id: 4,
  marks: {
    science: 80,
    maths: 89,
    english: 91
  }
}];


var inDetail = getPercentageAndRank(students);

function getPercentageAndRank(students) {

  var details = students.map(function(getMarks) {
    // console.log(((getMarks.marks.english + getMarks.marks.maths + getMarks.marks.science) / 3));
    return {
      name: getMarks.name,
      science: getMarks.marks.science,
      maths: getMarks.marks.maths,
      english: getMarks.marks.english,
      percentage: ((getMarks.marks.english + getMarks.marks.maths + getMarks.marks.science) / 3),
      rank: 0
    };
  }).sort(function(a, b) {
    return b.percentage - a.percentage;
  });

  for (var i = 0; i < details.length; i++) {
    // Updating the rank in order.
    details[i].rank = i + 1;
  }

  return details.map(function(gg) {
    return [
      gg.name,
      "has scored marks in Science -",
      gg.science,
      "Maths -",
      gg.maths,
      "English -",
      gg.english,
      "and secured", (gg.percentage).toFixed(2),
      "%", "and his rank is", gg.rank + "."
    ].join(' ');

  }).reduce(function(previous, current) {
    return previous + '\n' + current;
  }); // String result...
}
console.log(inDetail);

在这个问题中，您不需要使用筛选功能。

网页内容由stack overflow 提供, 点击上面的
可以查看英文原文，
原文链接