Android Java read file to list-CodePudding

I asked for more detailed help on this. But again I need help. I first worked in the compiler to read my file. Later, when I moved my code to the project, other problems arose. I had to use the getAssets() method to read the file. As a result, can you help me to create the same list again?

What I want to do is create a List<List<Double>> list. I am creating the same list as below but as List<String>.

The problem : when reading the file it takes each line as a string . for example "-0.140625000000000,0.986816000000000,-0.209473000000000"

My text file

-0.140625000000000,0.986816000000000,-0.209473000000000
-0.144531000000000,0.959473000000000,-0.262207000000000
-0.168945000000000,0.945312000000000,-0.340820000000000
-0.141602000000000,0.939453000000000,-0.289551000000000
-0.145508000000000,0.950195000000000,-0.305664000000000
-0.147461000000000,0.946777000000000,-0.302246000000000
-0.146484000000000,0.950684000000000,-0.305176000000000
-0.145996000000000,0.951660000000000,-0.305176000000000
  ....

For Example

List<List<double>> list =  [
   [-0.447266000000000, 0.417969000000000, 0.738770000000000], 
   [-0.447266000000000, 0.417969000000000, 0.738770000000000], 
   [-0.447266000000000, 0.417969000000000, 0.738770000000000], 
   [-0.447266000000000, 0.417969000000000, 0.738770000000000],
   [-0.447266000000000, 0.417969000000000, 0.738770000000000]
 ]

My code

The code I got in the comment line was my old working code.

    public void myPatienListMethod() {

    List<List<Double>> myList = new ArrayList<>();
    List<String> myLists = new ArrayList<>();

    //try (CSVReader reader = new CSVReader( new FileReader(fileName))) {
    //List<String[]> r = reader.readAll();
    // r.forEach(lineArr -> {
    //      List<Double> line = new ArrayList<>();
    //        for (String str : lineArr) {
    //      line.add(Double.parseDouble(str));
    //    }
    //      myList.add(line);
    //    });
    //  }

    String filename = "aaa.txt";
    BufferedReader bufferedReader = null;

    try {
        bufferedReader = new BufferedReader(new InputStreamReader
                (this.getAssets().open(filename)));

        String line;

        while ((line = bufferedReader.readLine()) != null) {
            myLists.add(line);
            // Log.i("list", myLists.toString());
        }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (bufferedReader != null) {
            try {
                bufferedReader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

CodePudding user response：

I am sure there is already an answer to this, but i can't find it. You need to first split the line by the delimiter(looks like comma).

String[] strings = line.split(",");

Then you need to iterate the strings, parse each string to double and add it to the list.

List<Double> parsedLine = new ArrayList<>(strings.length);
for (String string : strings) {
    parsedLine.add(Double.parseDouble(string));
}

Or you can do the same with java 8 stream:

List<Double> parsedLine = Arrays.stream(line.split(","))
           .map(Double::parseDouble)
           .collect(Collectors.toList());