Java 计算 double - NaN

Question

使用下面的代码，变量( double )dAvgRun1、dAvgRun2(以及变量 dBest)在输出到 GUI 中的标签时返回为 NaN。

我在代码中做错了什么使我的 double 为 NaN？

            double [][] daRun = new double[2][7];

            //Sets Athlete Name and Nationality labels to selected athlete in JList
            jLabel_Athlete.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).sName);
            jLabel_Country.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).sCountry);

            //Returns all scores for selected athlete
            jTextField_Run1_0.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[0]);
            jTextField_Run1_1.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[1]);
            jTextField_Run1_2.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[2]);
            jTextField_Run1_3.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[3]);
            jTextField_Run1_4.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[4]);
            jTextField_Run1_5.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[5]);
            jTextField_Run1_6.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun1[6]);

            jTextField_Run2_0.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[0]);
            jTextField_Run2_1.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[1]);
            jTextField_Run2_2.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[2]);
            jTextField_Run2_3.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[3]);
            jTextField_Run2_4.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[4]);
            jTextField_Run2_5.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[5]);
            jTextField_Run2_6.setText(vecAthlete.get(jList_Athlete.getSelectedIndex()).saTempRun2[6]);

            //Parse all scores from string to double
            daRun[0][0] = Double.parseDouble(jTextField_Run1_0.getText());
            daRun[0][1] = Double.parseDouble(jTextField_Run1_1.getText());
            daRun[0][2] = Double.parseDouble(jTextField_Run1_2.getText());
            daRun[0][3] = Double.parseDouble(jTextField_Run1_3.getText());
            daRun[0][4] = Double.parseDouble(jTextField_Run1_4.getText());
            daRun[0][5] = Double.parseDouble(jTextField_Run1_5.getText());
            daRun[0][6] = Double.parseDouble(jTextField_Run1_6.getText());

            daRun[1][0] = Double.parseDouble(jTextField_Run2_0.getText());
            daRun[1][1] = Double.parseDouble(jTextField_Run2_1.getText());
            daRun[1][2] = Double.parseDouble(jTextField_Run2_2.getText());
            daRun[1][3] = Double.parseDouble(jTextField_Run2_3.getText());
            daRun[1][4] = Double.parseDouble(jTextField_Run2_4.getText());
            daRun[1][5] = Double.parseDouble(jTextField_Run2_5.getText());
            daRun[1][6] = Double.parseDouble(jTextField_Run2_6.getText());

            //Finds maximum and minimum scores for both runs
            int z;
            double dMinScoreRun1 = 10, dMaxScoreRun1 = 0;
            double dMinScoreRun2 = 10, dMaxScoreRun2 = 0;

            for (z=0; z<daRun.length; z++)
            {
                if (daRun[0][z] > dMaxScoreRun1)
                {dMaxScoreRun1 = daRun[0][z];}
                if (daRun[0][z] < dMinScoreRun1)
                {dMinScoreRun1 = daRun[0][z];}

                if (daRun[1][z] > dMaxScoreRun2)
                {dMaxScoreRun2 = daRun[1][z];}
                if (daRun[1][z] < dMinScoreRun2)
                {dMinScoreRun2 = daRun[1][z];}
            }


            //Calculates average scores
            double dTotalRun1 = 0, dTotalRun2 = 0;
            double dAvgRun1 = 0, dAvgRun2 = 0;

            //Run 1
            for (z=0; z<daRun.length; z++)
            {
                if(daRun[0][z] == dMaxScoreRun1 || daRun[0][z] == dMinScoreRun1)
                    continue;
                dTotalRun1 += daRun[0][z];
            }
            dAvgRun1 = dTotalRun1 / (daRun.length-2);

            //Run 2
            for (z=0; z<daRun.length; z++)
            {
                if(daRun[1][z] == dMaxScoreRun2 || daRun[1][z] == dMinScoreRun2)
                    continue;
                dTotalRun2 += daRun[1][z];
            }
            dAvgRun2 = dTotalRun2 / (daRun.length-2);

            //Displays averages for both runs
            jLabel_Average1.setText(Double.toString(dAvgRun1));
            jLabel_Average2.setText(Double.toString(dAvgRun2));

            //Compare both scores to find the best score.
            double dBest = dAvgRun1;

            if (dAvgRun2 > dAvgRun1)
            {
                dBest = dAvgRun2;
            }

            //Sets text of lblBestScore to the highest of the two scores 
            jLabel_Best.setText(Double.toString(dBest));

Answer 1

double [][] daRun = new double[2][7];

你用

dAvgRun1 = dTotalRun1 / (daRun.length-2);

这将执行 dTotalRun1/0。你可能想要

dAvgRun1 = dTotalRun1 / (daRun[0].length-2);

但这也是有问题的。如果有多个值等于最小值或最大值怎么办？你应该数数:

int cnt = 0;
for (z=0; z<daRun.length; z++){
    if(daRun[0][z] == dMaxScoreRun1 || daRun[0][z] == dMinScoreRun1)
          continue;
    dTotalRun1 += daRun[0][z];
    cnt++;
}

if( cnt != 0 ){
    dAvgRun1 = dTotalRun1 / cnt;
} else {
    // ? not sure what to use here
}