Java stream - get result after splitting a string twice

Question

I have a line:

String modulesToUpdate = "potato:module1, tomato:module2";

I want to get only from him:

module1
module2

First I need to break it into "," and then into ":"

So, I did this:

String files[] = modulesToUpdate.split(",");

for(String file: files){
    String f[] = file.split(":");
    for(int i=0; i<f.length; i++){
        System.out.println(f[1])
    }
}

This works, but the loop in the loop is not elegant.

I am trying to do the same with threads.

So, I did this:

Stream.of(modulesToUpdate)
            .map(line -> line.split(","))
            .flatMap(Arrays::stream)
            .flatMap(Pattern.compile(":")::splitAsStream)
            .forEach(f-> System.out.println(f.toString().trim()));

Output:

potato
module1
tomato
module2

How to reduce / filter it to get only:

module1
module2

Answer 1

Change one line:

  .map(x -> x.split(":")[1])

instead:

  .flatMap(Pattern.compile(":")::splitAsStream)

Or as @Holger mentions in a comment:

 .map(s -> s.substring(s.indexOf(':')+1))

it does not create an intermediate array at all.

That flatMapreturns Stream, and the streams have no indexes, but in this case you need them to go to the second token.

Answer 2

split .

,\s* ,, trim. , ( [^:]*?:) , .

: , . ,

Pattern.compile(",\\s*[^:]*?:")
       .splitAsStream(modulesToUpdate.substring(modulesToUpdate.indexOf(':')+1))
       .forEach(System.out::println);

, , ,

Pattern.compile("(^|,\\s*)[^:]*?:").splitAsStream(modulesToUpdate)
       .skip(1)
       .forEach(System.out::println);

Answer 3

skip flatMap, :

String modulesToUpdate = "potato:module1, tomato:module2";
Arrays.stream(modulesToUpdate.split(","))
.map(String::trim)
.flatMap(s -> Arrays.stream(s.split(":")).skip(1))
.forEach(System.out::println);

Answer 4

, :

• Array flow and collection of elements in odd positions

---

String modulesToUpdate = "potato:module1, tomato:module2";
String[] mod = modulesToUpdate.split("[:,]");
List<String> res = IntStream.range(0, mod.length)
                     .filter(j -> (j % 2) == 0)
                     .mapToObj(i -> mod[i])
                     .collect(Collectors.toList());
System.out.println(res);