In this tutorial, we will see “How to find the first non-repeated character in a string using Java 8?”find first non repeated character in a string using Java 8
Java 8 – How to find the First Non-Repeated Character in a String? Share on X
/**
* Find the First Non-Repeated Character in a String using Java 8
* @author Deepak Verma
*
*/
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
public class Find_First_Non_Repeated_Character_in_a_String_using_Java8 {
public static void main(String[] args) {
System.out.println("First Non-Repeated Character in the String: 'AMAZING' is: "+firstNonRepeatedCharacter("AMAZING"));
}
public static Optional<Character> firstNonRepeatedCharacter(String inputString) {
Map<Character, Long> characterCount = inputString.chars()
.mapToObj(c -> (char) c)
.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));
return inputString.chars()
.mapToObj(c -> (char) c)
.filter(c -> characterCount.get(c) == 1)
.findFirst();
}
}
Output:
First Non-Repeated Character in the String: 'AMAZING' is: Optional[M]
find first non repeated character in a string using Java 8
In the above example, The firstNonRepeatedCharacter method takes a String input which is supplied through the main method and returns an Optional<Character> which contains the first non-repeated character in the supplied string, or an empty Optional if there are no non-repeated characters present there. It uses stream API and collects the frequency of each character in the input string into a Map of Character to Long. The filtered stream of characters is later used to find the first character whose frequency is 1.
Java 8 – How to find the First Non-Repeated Character in a String? Share on X
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