Is there a concise way to iterate over a stream with indices in Java 8?

Question

Is there a concise way to iterate over a stream whilst having access to the index in the stream?

String[] names = {\"Sam\",\"Pamela\", \"Dave\", \"Pascal\",          


        

Answer 1

You can use IntStream.iterate() to get the index:

String[] names = {"Sam","Pamela", "Dave", "Pascal", "Erik"};
List nameList = IntStream.iterate(0, i -> i < names.length, i -> i + 1)
        .filter(i -> names[i].length() <= i)
        .mapToObj(i -> names[i])
        .collect(Collectors.toList());

This only works for Java 9 upwards in Java 8 you can use this:

String[] names = {"Sam","Pamela", "Dave", "Pascal", "Erik"};
List nameList = IntStream.iterate(0, i -> i + 1)
        .limit(names.length)
        .filter(i -> names[i].length() <= i)
        .mapToObj(i -> names[i])
        .collect(Collectors.toList());