How to modify elements inside List using stream and ignore last element?

Issue

I have the following list:

var list = Arrays.asList("a", "b", "c");

I want to achieve something like that:

// "a, "
// "b, "
// "c"

So I did that:

var formattedList = list.stream()
        .map(el -> el + ", ")
        .collect(Collectors.toList());

It is working almost fine:

// "a, "
// "b, "
// "c, "

but as you can see I don't know how to "ommit" last element in my stream.

Could someone help me achieve that?

Solution

You can use String.join()

var list = Arrays.asList("a", "b", "c");
String.join(",", list) // returns a,b,c

I assumed you wanted to join the elements. But if you don't, I think stream api is not suitable for this. Traditional iterator would work better. Because your requirement is based on index of the element. In streams, index information is not provided.

Answered By - Taha