Java 8 enhanced for loop with index/range

Question

Is it possible to specify an index/range in enhanced for loop in Java?

For eg I have a list: List<String> list;

And I want to run a for loop from index 1 instead of 0:

for(String s : list(start from index 1))

OR till index 5

for(String s : list(end at index 5))

I know I can use traditional for loop or keep a counter inside the enhanced for loop but I wanted to know is there something out of the box in Java or apache collections?

Answer 1

I would use subList in this case:

for(String s : list.subList(1, list.size()))

and

for(String s : list.subList(0, 6))

Answer 2

Using of sublist is better but stream version is using skip and limit :

list.stream().skip(1) .... limit(6)..... 

Answer 3

In the Java 8 we have Stream API, which we could use to iterate over List with custom indexes:

List<String> evenIndexes = IntStream
  .range(0, names.length)
  .filter(i -> i % 2 == 0)
  .mapToObj(i -> names[i])
  .collect(Collectors.toList());

in the range method, you could start from 1, and/or iterate to 5.

Answer 4

The traditional for loop is the "out of the box" solution for this requirement:

for (int i = 1; i < list.size(); i++) {
    String s = list.get(i);
    ...
}

and (if the List has at least 5 elements):

for (int i = 0; i < 5; i++) {
    String s = list.get(i);
    ...
}

Answer 5

I am not sure of the performance penalty, but you can use List::subList

List<String> list = Arrays.asList("a", "b", "c");

for (String s : list.subList(1, list.size())) {
        System.out.println(s);
}

output

2
3

Answer 6

It is possible with list.subList(1, list.size()) , but it will add performance penalty for sublisting list. It is better to use traditional for loop in this case.

//Calculate size first to avoid performance penalty calculating in loop each iteration

int size = list.size();

for (int i = 1; i < size; i++) {
    String s = list.get(i);
    ...
}

Answer 7

You can use it

for(int i=1 ; i< list.size ; i++){
   String str = list.get(i);
}