Question

我需要通过for in循环显示最高值。我有三个部门要显示，但是在for in循环之后它不想接受并给我最高价值。

到目前为止，代码成功循环并为我提供了所需的结果。它应该console.log我将户外作为最有利可图的部门。

这是我的作业，只是澄清因为我不是在寻找答案，只是澄清如何去做。简单而彻底。

var salesData = [
  {department : 'hardware', sales : 4500, day : 'Monday'},
  {department : 'outdoor', sales : 1500, day : 'Monday'},
  {department : 'carpentry', sales : 5500, day : 'Monday'},
  {department : 'hardware', sales : 7500, day : 'Tuesday'},
  {department : 'outdoor', sales : 2505, day : 'Tuesday'},
  {department : 'carpentry', sales : 1540, day : 'Tuesday'},
  {department : 'hardware', sales : 1500, day : 'Wednesday'},
  {department : 'outdoor', sales : 8507, day : 'Wednesday'},
  {department : 'carpentry', sales : 8009, day : 'Wednesday'},
  {department : 'hardware', sales : 12000, day : 'Thursday'},
  {department : 'outdoor', sales : 18007, day : 'Thursday'},
  {department : 'carpentry', sales : 6109, day : 'Thursday'},
  {department : 'hardware', sales : 7005, day : 'Friday'},
  {department : 'outdoor', sales : 12006, day : 'Friday'},
  {department : 'carpentry', sales : 16109, day : 'Friday'},
];

function mostProfitableDepartment(salesList) {
  //group by department`
  var salesForEachDepartment = {};
  var high = 0;

  //loop through all the sales
  for (var i = 0; i < salesList.length; i++) {
    //salesForEachDepartment += salesList[i];

    var deptDailySale = salesList[i];

    //check if the current department is in the salesForEachDepartment map
    if (salesForEachDepartment[deptDailySale.department] === undefined) {
      salesForEachDepartment[deptDailySale.department] = 0;
    }

    salesForEachDepartment[deptDailySale.department] += deptDailySale.sales;
    //deptDailySale.department
    //if ()
  }
  console.log(salesForEachDepartment);
}

mostProfitableDepartment(salesData);

for (var highestDepSale in salesForEachDepartment[deptDailySale.sales]) {
  if (salesForEachDepartment[highestDepSale.sales] > highestDepSale) {
    highestDepSale = salesForEachDepartment[highestDepSale.sales];
  }
  console.log(highestDepSale);
}

Answer 1

您应该在循环

之前先对salesList进行排序

salesList = salesList.sort(function (a, b) {
    return b.sales - a.sales; // desc
});

Answer 2

salesForEachDepartment的结构是

{
  "hardware": 32505,
  "outdoor": 42525,
  "carpentry": 37267
}

因此，当您执行salesForEachDepartment[deptDailySale.sales]时，您只能访问一个值。因此，您只获得第一个价值。

你只需要使用

for (var k in salesForEachDepartment) {
  if (salesForEachDepartment[k] > max)
    max = salesForEachDepartment[k];
}

您的代码已更新

var salesData = [
  {department : 'hardware', sales : 4500, day : 'Monday'},
  {department : 'outdoor', sales : 1500, day : 'Monday'},
  {department : 'carpentry', sales : 5500, day : 'Monday'},
  {department : 'hardware', sales : 7500, day : 'Tuesday'},
  {department : 'outdoor', sales : 2505, day : 'Tuesday'},
  {department : 'carpentry', sales : 1540, day : 'Tuesday'},
  {department : 'hardware', sales : 1500, day : 'Wednesday'},
  {department : 'outdoor', sales : 8507, day : 'Wednesday'},
  {department : 'carpentry', sales : 8009, day : 'Wednesday'},
  {department : 'hardware', sales : 12000, day : 'Thursday'},
  {department : 'outdoor', sales : 18007, day : 'Thursday'},
  {department : 'carpentry', sales : 6109, day : 'Thursday'},
  {department : 'hardware', sales : 7005, day : 'Friday'},
  {department : 'outdoor', sales : 12006, day : 'Friday'},
  {department : 'carpentry', sales : 16109, day : 'Friday'},
];

function mostProfitableDepartment(salesList) {
  //group by department`
  var salesForEachDepartment = {};
  var high = 0;

  //loop through all the sales
  for (var i = 0; i < salesList.length; i++) {
    //salesForEachDepartment += salesList[i];

    var deptDailySale = salesList[i];

    //check if the current department is in the salesForEachDepartment map
    if (salesForEachDepartment[deptDailySale.department] === undefined) {
      salesForEachDepartment[deptDailySale.department] = 0;
    }

    salesForEachDepartment[deptDailySale.department] += deptDailySale.sales;
    //deptDailySale.department
    //if ()
  }
  console.log(salesForEachDepartment);

  var max = 0;
  for (var k in salesForEachDepartment) {
    if (salesForEachDepartment[k] > max)
      max = salesForEachDepartment[k];
  }
  console.log(max)
}

mostProfitableDepartment(salesData);

您可以使用Array.forEach + for..in + Math.max

var salesData = [
  {department : 'hardware', sales : 4500, day : 'Monday'},
  {department : 'outdoor', sales : 1500, day : 'Monday'},
  {department : 'carpentry', sales : 5500, day : 'Monday'},
  {department : 'hardware', sales : 7500, day : 'Tuesday'},
  {department : 'outdoor', sales : 2505, day : 'Tuesday'},
  {department : 'carpentry', sales : 1540, day : 'Tuesday'},
  {department : 'hardware', sales : 1500, day : 'Wednesday'},
  {department : 'outdoor', sales : 8507, day : 'Wednesday'},
  {department : 'carpentry', sales : 8009, day : 'Wednesday'},
  {department : 'hardware', sales : 12000, day : 'Thursday'},
  {department : 'outdoor', sales : 18007, day : 'Thursday'},
  {department : 'carpentry', sales : 6109, day : 'Thursday'},
  {department : 'hardware', sales : 7005, day : 'Friday'},
  {department : 'outdoor', sales : 12006, day : 'Friday'},
  {department : 'carpentry', sales : 16109, day : 'Friday'},
];

var groupedData = {}
salesData.forEach(function(o){
  groupedData[o.department] = (groupedData[o.department] || 0) + o.sales;
});

var max = 0;
for (var k in groupedData){
  max = Math.max(groupedData[k], max);
}
console.log(max)

无法获得最高显示

2 个答案: