How to get unique values in List

java list unique-values
Junior Fulcrum picture Junior Fulcrum · Oct 2, 2014 · Viewed 31k times · Source

I have 2 text files with data. I am reading these files with BufferReader and putting the data of one column per file in a List<String>.

I have duplicated data in each one, but I need to have unique data in the first List to confront with the duplicated data in the second List.

How can I get unique values from a List?

Answer

Bohemian picture Bohemian · Oct 2, 2014

It can be done one one line by using an intermediate Set:

List<String> list = new ArrayList<>(new HashSet<>(list));

In java 8, use distinct() on a stream:

List<String> list = list.stream().distinct().collect(Collectors.toList());

Alternatively, don't use a List at all; just use a Set (like HashSet) from the start for the collection you only want to hold unique values.

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