Java在子字符串中找到两个中位数

Question

new to java here and I have a nooby question.

I was recently given this txt file:

Albuquerque, New Mexico, 5352 feet, 202.3°
Denver, Colorado, 5280 feet, 202.4°
Minneapolis, Minnesota, 841 feet, 210.5°
Birmingham, Alabama, 644 feet, 210.8°
Detroit, Michigan, 639 feet, 210.8°
Miami, Florida, 11 feet, 211.9°
Burj Khalifa, Dubai, 2717 feet, 207.1°
CN Tower, Toronto, 1815 feet, 208.7°

and was ask to find and printout the two median number. Problem is I keep getting error when I try to use Arrays.sort() .

public static void main(String[] args) {
    File mf = new File("C:\\file.txt");
    ArrayList<String> inData = new ArrayList<String>();
    String strline;

    try {
        FileInputStream fstream = new FileInputStream(mf);
        BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
        while ((strline = br.readLine()) != null) {
            strline = strline.trim();
            if ((strline.length() != 0)) {
                inData.add(strline);
            }
        }
        br.close();
    } catch (Exception e) {
        System.err.println("Error CANNOT FIND FILE!");
    }

    //Calc median start
    double median;
    for (int i = 0; i < inData.size(); i++) {
        String[] word = inData.get(i).split(", ");
        double m = Double.parseDouble(word[3].substring(0, 5));
        Arrays.sort(m);
        if (m.length % 2 == 0) {
            double middleNumOne = m[m.length / 2 - 0.5]
            double middleNumTwo = m[m.length / 2 + 0.5]
            System.out.println("Median:" + middleNumOne + "and" + middleNumTwo);
        }
    }
}

this is what i have so far. Can someone please help me, and tell me what am I missing?

Answer 1

Just to spell it out for you, this is what you need to change:

double[] median = new double[inData.size()];

for (int i=0; i < inData.size(); i++) {
    String[] word = inData.get(i).split(", "); 
    double m = Double.parseDouble(word[3].substring (0,5));
    median[i] = m;
}

Arrays.sort(median);

And then every reference to m after this point in your code should be changed to median .

Answer 2

You can't use Arrays.sort(m); the m var is a double i guess you mean Array.sort(word) and so on in the rest of the code...

If you need to create a double array to calculate the median, check this question

Answer 3

    List<Double> altitudes = new ArrayList<Double>();
    for (int i = 0; i < inData.size(); i++) {
        String[] word = inData.get(i).split(", ");
        double m = Double.parseDouble(word[3].substring(0, 5));
        altitudes.add(m);
    }
    Double[] array = altitudes.toArray(new Double[] {});
    Arrays.sort(array);
    for (Double double1 : array) {
        System.out.println(" " + double1);
    }
    if (array.length % 2 == 0) {

        double middleNumOne = array[(int) (array.length / 2 - 0.5)];
        double middleNumTwo = array[(int) (array.length / 2 + 0.5)];

        System.out.println("Median: " + middleNumOne + " and " + middleNumTwo);
    }