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I have some rows of numbers in String str;
Numbers split by TAB 

1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
\\... many others, ~ 2 000 strings

I need split columns with

1 numbers to massive1,
2 numbers to massive2,
3 numbers to massive3,
4 numbers to massive4,
5 numbers to massive5,
6 numbers to massive6

I know how to solve this task with many for / while loops but I need compact solve for this task. Maybe I need Patern.compile or String.split?

Some of my code:

for (i = 0; i <= fileLen; i++) {
  while (s.charAt(i) != 13 && s.charAt(i + 1) != 10) {

    while (s.charAt(i) != 9) {
      n1.add((int) s.charAt(i));
      i++;
    }
    // skip TAB
    i++;
    // next for other column
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9
  • Can you post the code you have so far? Commented May 23, 2019 at 12:36
  • what do you mean by 1 numbers to massive1 ? Commented May 23, 2019 at 12:42
  • for (i=0; i<=fileLen; i++){ while ( s.charAt(i) != 13 && s.charAt(i+1) != 10) { // EOS while (s.charAt(i) != 9) // TAB { n1.add((int)s.charAt(i)); i++; } // skip TAB i++; Commented May 23, 2019 at 12:43
  • 2
    Expected output may help to explain what you need. Commented May 23, 2019 at 12:45
  • @Hades: <code>I need, 1 all column store into massive1: 1 . . . . . 1 . . . . . 1 . . . . . Next need, 2 column store into massive2: . 2 . . . . . 2 . . . . . 2 . . . . Next need, 3 column store into massive3: . . 3 . . . . . 3 . . . . . 3 . . . Next need, 4 column store into massive4: . . . 4 . . . . . 4 . . . . . 4 . . Next need, 5 column store into massive5: . . . . 5 . . . . . 5 . . . . . 5 . Next need, 6 column store into massive6: . . . . . 6 . . . . . 6 . . . . . 6 . . . . . 6<code> Commented May 23, 2019 at 12:58

2 Answers 2

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1

Instead of variables massive1, ..., massive6 a variable lenght List massives would be more suitable:

List<List<Integer>> massives = Arrays.stream(str.split("\\R"))  // Stream<String>
    .map(line -> Arrays.stream(line.split("\t"))                  //   Stream<String>
         .map(field -> Integer::valueOf)                          //   Stream<Integer>
         .collect(Collectors.toList()))                           //   List<Integer>
     .collect(Collectors.toList());                             // List<List<Integer>>

List<int[]> massives = Arrays.stream(str.split("\\R"))
     .map(line -> Arrays.stream(line.split("\t"))
         .mapToInt(Integer::parseInt)
         .toArray())
     .collect(Collectors.toList());

Maybe with:

massive1 = massives.get(0);
massive2 = massives.get(1);
massive3 = massives.get(2);
massive4 = massives.get(3);
...

Explanation:

  • String[] String#split(String regex) would split using the line-break match (\\R) into several lines.
  • Stream.of / Arrays.stream turns String[] into Stream<String> a kind of iteration through every String.
  • Stream.map turns turns every String when using Integer::valueOf into an Integer.
  • Stream.collect collects every Integer into a List.

Streams are very expressive, but might not be suited for total beginners, as they combine all into one single expression, which may easily cause errors.

After understanding the question:

int[][] rows = Stream.of(str.split("\\R"))
    .map(line -> Stream.of(line.split("\\s+"))
        .mapToInt(Integer.parseInt)
        .toArray())
    .toArray(int[][]::new);

However one wants the columns:

int m = rows.length;
int n = Arrays.stream(rows).mapToInt(line -> line.length).min().orElse(0);

int[][] columns = IntStream.range(0, n)
    .mapToObj(j -> IntStream.range(0, m)
        .map(i -> rows[i][j])
        .toArray()).toArray(int[][]::new);

System.out.println(Arrays.deepToString(columns));

Actually I advise to convert rows to columns by classical for-loops; much better readable.

But a StackOverflow answer should not necessarily pick the easiest way.

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4 Comments

Sorry for delay in answer. I have errors when I'm compile this code: ~~Error:(82, 33) java: incompatible types: cannot infer type-variable(s) R (argument mismatch; bad return type in lambda expression java.lang.Object is not a functional interface) Error:(84, 29) java: incompatible types: inference variable T has incompatible bounds equality constraints: java.util.List<java.lang.Integer>~~
field -> Integer::parseInt should have been either field -> Integer.parseInt(field) or the correction in the answer.
List<List<Integer>> massives = Arrays.stream(str.split("\\R")) .map(line -> Arrays.stream(line.split("\t")) .map(field -> Integer.parseInt(field)) .collect(Collectors.toList())) .collect(Collectors.toList()); // out [[1, 2, 3, 4, 5, 6], [1, 2, 3, 4, 5, 6] // I need out [[1, 1, 1, 1, 1, 1], [2, 2, 2, 2, 2, 2]
Joop Eggen: Big thanks! its code work for me. I'm master of intelligible explanation(no)
1

Here you go,

    String str = "1 2 3 4 5 6 \n 1 2 3 4 5 6 \n 1 2 3 4 5 6";
    Arrays.asList(str.split("\n")).stream().map((s) -> s.split(" ")).map((splitBySpace) -> {
        for (String sp : splitBySpace) {
                System.out.print(sp);
            }
            return splitBySpace;
        }).forEachOrdered((String[] _item) -> {
            System.out.println();
    });

---Output---
123456
123456
123456

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1 Comment

Must be: mas1 = "111"; mas2="222"; mas="333"; ... mas1 - its first column, mas2=second column; In your example row(without spaces) not column. Sorry for bad explanations.

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