Split string and add unique strings to list in java

Question

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.

Answer 1

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

[hello, hi, henry, hello1, hi1, henry1]