查找2D数组行的平均值

Question

我创建的方法可以找到2D数组中一行的平均值。该方法接受描述作为行的等级类别的字符。从那以后，我需要找到该行中所有项目的平均值。如何找到行并计算平均值？

这是我到目前为止所拥有的：

import java.util.Arrays;

public class GradeBook {

private String name;
private char[] categoryCodes;
private String[] categories;
private double[] categoryWeights;
private double[][] gradeTable;

public GradeBook(String nameIn, char[] categoryCodesIn, 
  String[] categoriesIn, double[] categoryWeightsIn) {

  name = nameIn;
  categoryCodes = categoryCodesIn;
  categories = categoriesIn;
  categoryWeights = categoryWeightsIn;
  gradeTable = new double[5][0];
 }
 public double categoryAvg (char gradeCategory) {

    double sum = 0.0;
    double count = 0.0;
    int index = 0; 

    if (gradeCategory == 'a')
        index = 0;
    else if (gradeCategory == 'q')
        index = 1;
    else if (gradeCategory == 'p')
        index = 2;
    else if (gradeCategory == 'e')
        index = 3;
    else if (gradeCategory == 'f')
        index = 4;

    return sum / count;
  }
}

Answer 1

选择行后，您只需在该行上进行简单的1D阵列平均。 类似的东西：

for(int i=0; i < array[index].length; i++){
      sum = sum + array[index][i];
      count++;
}

Answer 2

你应该添加这样的东西到最后，所以你不要试图除以零：

if (count == 0) {
    return 0;
} else {
    return sum / count;
}