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Convert and collect unique cities

A travel agency stores city names in lowercase. Before displaying them in brochures, all city names need to be converted to uppercase and stored in a Set to ensure uniqueness.

Cet exercice fait partie du cours

Input/Output and Streams in Java

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Instructions

  • Convert each city name to uppercase letter using .map().
  • Collect the result using .collect().
  • Collect the result in a Set using predefined collect strategy.

Exercice interactif pratique

Essayez cet exercice en complétant cet exemple de code.

import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

public class CityProcessor {
    public static void main(String[] args) {
        List cities = List.of("paris", "london", "new york", "paris");

        Set uniqueUppercaseCities = cities.stream()
        	//Convert each city name to uppercase
            .____(city -> city.toUpperCase())
             // Collect the result and store into a Set
            .____(____);

        System.out.println(uniqueUppercaseCities);
    }
}
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