Get distinct elements from java string array

Question

I have a string array as below.

String [] exmp = {"Example ExamPle", "Example"};

I want to get distinct element from the above array irrespective of character case.

I need to get the below output for above array. "Example"

I have tried with the following code.

LinkedHashSet<String> set = new LinkedHashSet<String>();

String [] exmp = {"Example ExamPle", "Example"};

for(String s : exmp) {

String unqWrds = Arrays.stream(s.split("\\s+")).distinct().collect(Collectors.joining(" "));

set.add(unqWrds);

}

But currently I am getting entire string getting added to set due to case difference "Example ExamPle", "Example"

Could you please advise here.

Are you asking how to ignore the case difference? Because the example you chose is problematic. I don’t understand how you define distinct . If it was “example example example” would it still be the same? — sagi
– sagi, Commented Nov 22, 2019 at 13:27
There are two distinct elements in the array. Now if the array was {"Example", "ExamPle", "Example"}, there would be one distinct value when you ignore case. — Andreas
– Andreas, Commented Nov 22, 2019 at 13:28
And is “a a a a” the same as “a a a”? What’s the logic — sagi
– sagi, Commented Nov 22, 2019 at 13:28

Andreas · Accepted Answer · 2019-11-22 13:39:37Z

According to the sample code in the question, you want to split the strings on whitespace, even though you never said that in the question.

You then try to use distinct(), but that will unfortunately not work, because distinct() doesn't take a Comparator, so it cannot compare case-insensitively.

To get your desired result:

// Using loops
public static Set<String> distinctWords(String... input) {
    Set<String> distinct = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
    for (String s : input)
        for (String word : s.trim().split("\\s+"))
            distinct.add(word);
    return distinct;
}

// Using streams
public static Set<String> distinctWords(String... input) {
    return Stream.of(input)
            .flatMap(s -> Stream.of(s.split("\\s+")))
            .collect(Collectors.toCollection(() -> new TreeSet<>(String.CASE_INSENSITIVE_ORDER)));
}

The TreeSet will keep the capitalization of the first word seen, and will sort the words, so the result of calling with {"Example ExamPle", "example"} is the desired result [Example].

Raztyck · Accepted Answer · 2019-11-22 13:33:09Z

0

Try that:

String unqWrds = Arrays.stream(s.split("\\s+")).reduce("", (x, y) -> x.toUpperCase().contains(y.toUpperCase()) ? x : x + " " + y);

answered Nov 22, 2019 at 13:33

Raztyck

887 bronze badges

Comments

lainatnavi · Accepted Answer · 2019-11-22 13:43:32Z

0

The ignore case part can be done like this:

String unqWrds = Arrays.stream(s.split("\\s+")).map(String::toLowerCase).distinct().collect(Collectors.joining(" "));

edited Nov 22, 2019 at 13:43

answered Nov 22, 2019 at 13:38

lainatnavi

1,6331 gold badge19 silver badges23 bronze badges

Collectives™ on Stack Overflow

Get distinct elements from java string array

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related