java - 如何将循环的结果放入带有索引的字符串中？

Question

我正在尝试构建一个字符串，并将循环结果放入将“att”转换为索引为“i”的字符串。因此，我可以对字符串进行排序并输出出勤率最高的学校及其学校编号。谢谢!

import java.util.Scanner;

public class PengjuShanP1 {

    public static void main(String[] args) {
        Scanner scnr = new Scanner(System.in);
        System.out.print("How many schools do you have in your district: ");
        int nos = scnr.nextInt();
        int[] nums = new int[nos];
        System.out.println();

        double ax  = 0;

        for (int i = 1; i < nos + 1; ++i) {
             System.out.println("Enter data for school " + i);
             System.out.print("   How many students are enrolled in school : ");
             int num = scnr.nextInt();



             System.out.print("   Enter the attendance for day 1: ");
             int d1 = scnr.nextInt();


             System.out.print("   Enter the attendance for day 2: ");
             int d2 = scnr.nextInt();

             System.out.print("   Enter the attendance for day 3: ");
             int d3 = scnr.nextInt();

             System.out.print("   Enter the attendance for day 4: ");
             int d4 = scnr.nextInt();

             System.out.print("   Enter the attendance for day 5: ");
             int d5 = scnr.nextInt();

             double avg = ((d1 + d2 + d3 + d4 + d5) / 5) * 100;
             double att = avg / num;
             ax = att + ax;

             System.out.println();

             System.out.println("Attendance " + att + "% for school " + i);
             System.out.println();
        }
        System.out.print(ax);
    }
}

Answer 1

编辑

鉴于学校 ID 是一个整数，可以在一个简单的数组中执行此操作，这比下面的集合 API 更节省空间和时间。

尽早初始化一个double数组:

double[] schools = new double[nos];

在循环中添加数据:

schools[i] = att;

并在最后找到最高的，并打印:

double highest = 0;
int index = 0;
for (int i = 0; i < schools.length; i++)
{
  if (schools[i] > highest)
  {
    index = i;
    highest = schools[i];
  }
}
System.out.println("The school with the best attendance is school " + (index + 1) + " with " + highest + "% attendance");

完整示例:

import java.util.Scanner;

public class ValuePairSortingSimpler
{
  public static void main(String[] args)
  {
    Scanner scnr = new Scanner(System.in);
    System.out.print("How many schools do you have in your district: ");
    int nos = scnr.nextInt();
    double[] schools = new double[nos];
    System.out.println();

    double ax = 0;

    for (int i = 0; i < nos; i++)
    {
      System.out.println("Enter data for school " + (i + 1));
      System.out.print("   How many students are enrolled in school : ");
      int num = scnr.nextInt();

      System.out.print("   Enter the attendance for day 1: ");
      int d1 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 2: ");
      int d2 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 3: ");
      int d3 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 4: ");
      int d4 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 5: ");
      int d5 = scnr.nextInt();

      double avg = ((d1 + d2 + d3 + d4 + d5) / 5) * 100;
      double att = avg / num;
      schools[i] = att;
      ax = att + ax;

      System.out.println();

      System.out.println("Attendance " + att + "% for school " + (i + 1));
      System.out.println();
    }
    double highest = 0;
    int index = 0;
    for (int i = 0; i < schools.length; i++)
    {
      if (schools[i] > highest)
      {
        index = i;
        highest = schools[i];
      }
    }
    System.out.println("The school with the best attendance is school " + (index + 1) + " with " + highest + "% attendance");
    System.out.print(ax);
  }
}

原帖:

我不确定字符串是这里的最佳路线。如果我没记错的话，您希望将多对值存储在列表或数组中，然后按其中一个值进行排序。使用集合 API 可以最好地解决这个问题。举个例子:

在开头(循环之前)定义键值对列表。键是学校 ID，值是出勤率。

List<Map.Entry<Integer, Double>> schools = new ArrayList<>();

然后将数据添加到循环中的列表中:

schools.add(Map.entry(i, att));

最后，按值降序排序(最高的在前)，然后打印结果。

schools.sort((a,b)->(int)Math.round(b.getValue()-a.getValue()));
System.out.println("The school with best attendance is school " + schools.get(0).getKey() + " with " + schools.get(0).getValue() + "% attendance!");

完整示例如下:

  public static void main(String[] args)
  {
    Scanner scnr = new Scanner(System.in);
    System.out.print("How many schools do you have in your district: ");
    int nos = scnr.nextInt();
    List<Map.Entry<Integer, Double>> schools = new ArrayList<>();
    System.out.println();

    double ax = 0;

    for (int i = 1; i < nos + 1; ++i)
    {
      System.out.println("Enter data for school " + i);
      System.out.print("   How many students are enrolled in school : ");
      int num = scnr.nextInt();

      System.out.print("   Enter the attendance for day 1: ");
      int d1 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 2: ");
      int d2 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 3: ");
      int d3 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 4: ");
      int d4 = scnr.nextInt();

      System.out.print("   Enter the attendance for day 5: ");
      int d5 = scnr.nextInt();

      double avg = ((d1 + d2 + d3 + d4 + d5) / 5) * 100;
      double att = avg / num;

      schools.add(Map.entry(i, att));

      ax = att + ax;

      System.out.println();

      System.out.println("Attendance " + att + "% for school " + i);
      System.out.println();
    }
    System.out.print(ax);
    schools.sort((a,b)->(int)Math.round(b.getValue()-a.getValue()));
    System.out.println("The school with best attendance is school " + schools.get(0).getKey() + " with " + schools.get(0).getValue() + "% attendance!");
  }