Best way to convert an ArrayList to a string

Question

I have an ArrayList that I want to output completely as a String. Essentially I want to output it in order using the toString of each element separated by tabs. Is there any fast way to do this? You could loop through it (or remove each element) and concatenate it to a String but I think this will be very slow.

Answer 1

In Java 8 or later:

String listString = String.join(", ", list); 

In case the list is not of type String, a joining collector can be used:

String listString = list.stream().map(Object::toString)                         .collect(Collectors.joining(", ")); 

Answer 2

If you happen to be doing this on Android, there is a nice utility for this called TextUtils which has a .join(String delimiter, Iterable) method.

List<String> list = new ArrayList<String>(); list.add("Item 1"); list.add("Item 2"); String joined = TextUtils.join(", ", list); 

Obviously not much use outside of Android, but figured I'd add it to this thread...