Java Split file lines into two lists

Question

I'm currently writing an app that takes the data from the file. I need to sort the data in different ways. The problem is that the file is in format:

NAME1(tab)A(tab)B
NAME2(tab)C(tab)D

I want to split data into two ArrayLists, one will gather NAME1, NAME2 etc, so the first element of line, the second list will gather the rest.

Here's my code:

Scanner scan = new Scanner(new File(fname));

while(scan.hasNext()){

}
scan.close();

System.out.println("Lang: ");
for(String item : lang)
    System.out.print(item + " ");

} catch (FileNotFoundException e) {
    e.printStackTrace();
}

I tried to play with scanner methods, but there are no results and I have no idea what to do.

You might wanna check scan.hasNextLine(). This reads line by line — riadrifai, Dec 05 '17 at 16:01
possible duplicate with https://stackoverflow.com/questions/3481828/how-to-split-a-string-in-java — Ahmad Al-Kurdi, Dec 05 '17 at 16:02

score 1 · Answer 1 · answered Dec 05 '17 at 16:05

Here is the recipe

fileInputStreamObj = StreamTests.class.getResourceAsStream(your_file_path);
bufferedReaderObj = new BufferedReader(new InputStreamReader(fileInputStreamObj));

bufferedReaderObj
  .lines()
  .map(s -> {
    String[] splitStrings = s.split("\t", -1);
    return Arrays.asList(splitStrings);
  }).forEach(System.out::println);

Some thing that I tested .

David Pérez Cabrera · Answer 2 · 2017-12-11T22:05:05.143

1

Here is my attempt:

List<String> list1 = new ArrayList<>();
List<String> list2 = Files.lines(Paths.get(fname)).flatMap(s -> {
    String[] line = s.split("\\t");
    if (line.length > 0) {
        list1.add(line[0]);
    }
    return Arrays.stream(line).skip(1);
}).collect(Collectors.toList());

edited Dec 11 '17 at 22:05

answered Dec 05 '17 at 16:12

David Pérez Cabrera

4,960
2
23
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1

Shorter (and probably better suited for memory usage): `Files.lines(Paths.get(fname)).flatMap(...`. – Olivier Grégoire Dec 05 '17 at 16:17
@OlivierGrégoire You are right, I known that but I did not remember the exact name of this function. – David Pérez Cabrera Dec 11 '17 at 22:06

score 0 · Answer 3 · answered Dec 05 '17 at 16:01

0

I would just use Scanner.nextLine(), then String.split("\t") and then append the line's parts to the respective lists.

answered Dec 05 '17 at 16:01

Stefan Reich

1,000
9
12

Java Split file lines into two lists

3 Answers3