Split string and add unique strings to list in java

November 11, 2021

I have the following list of strings containing words.

List<String> words = new ArrayList();
words.add("hello, hi, henry");
words.add("hello1, hi1, henry1");
words.add("hello, hi, henry");

How can I loop through the words list, extract each element separated by a comma and generate a new list with unique elements. Output list should contain only the unique elements from the original list: hello, hi, henry, hello1, hi1, henry1. Wondering if there is an easier way to do this using streams in java 8 Thank you.

>Solution :

Here is one approach.

Stream the list.
split each string on the comma.
flatMap each array to single stream of words.
trim the white space from each word.
use distinct to ignore duplicates.
assign to a list.

List<String> result = words.stream()
                .flatMap(str -> Arrays.stream(str.split(",")))
                .map(String::trim).distinct().toList();

System.out.println(result);

Prints