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javastringarrayliststring-concatenation

Java ArrayList<String> to single string without using loop

I have an ArrayList<String> that is added to periodically. What I want to do is to cast the entire ArrayList to a String without doing a loop. Can anybody tell me is it possible without using loop?

Edited: So we found some solutions, Like

list.stream().collect(Collectors.joining());

Or

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

or some others as well. Now Just for getting knowledge I put a question which one is the most optimal way for compiler?

Solution

  • You could make a stream out of your list and collect it using joining collector :

    list.stream().collect(Collectors.joining());

    You can pass the separator to Collectors::joining method for example :

    list.stream().collect(Collectors.joining("-"));

    Or you can use String::join method :

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

    where , is the separator.