Create formatted string from ArrayList

Question

Consider following code:

    ArrayList aList = new ArrayList();
    aList.add(2134);
    aList.add(3423);
    aList.add(4234);
         


        

Answer 1

Building off Mateusz's Java 8 example, there's an example in the StringJoiner JavaDoc that nearly does what OP wants. Slightly tweaked it would look like this:

List numbers = Arrays.asList(1, 2, 3, 4);

String commaSeparatedNumbers = numbers.stream()
     .map(i -> i.toString())
     .collect( Collectors.joining(",","(",")") );