for loop using lambda expression in JAVA

Question

My Code:

List ints = Stream.of(1,2,4,3,5).collect(Collectors.toList());
ints.forEach((i)-> System.out.print(ints.get(i-1)+ \" \"));
         


        

Answer 1

List indexes in Java are 0-based.

Therefore:

ints.get(0) == 1;
ints.get(1) == 2;
ints.get(2) == 3;
//etc...

You're calling ints.get(i-1) for each "i" where "i" is equal to the value of each element in the list "ints".

If you were to call ints.get(i) you'd be fetching elements with indices equal to 1,2,3,4 and 5 and 5 wouldn't be a valid index into a list with 5 elements.

---

This code:

ints.forEach((i)-> System.out.print(ints.get(i-1)+ " "));

is equivalent to:

for(int i : ints ) {
    System.out.print(ints.get(i-1) + " ");
}

Your examples aren't equivalent.