CODEWITHSUNDEEP
javaandroid
Hernan
Hernan

Reputation: 59

Compare list using a different variable if list items have the same value in one variable

I have a class Person with the attributes of name (string) and age (int):

public class Person {
    private String name;
    private int age;

    public Hero(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

I created a list of Person, and compared them using age.

List<Person> persons = new ArrayList<>();
persons.add("Andrew", 18);
persons.add("Barry", 25);
persons.add("Cynthia", 33);
persons.add("Darwin", 33);

Collections.sort(persons, new Comparator<Person>() {
    @Override
    public int compare(Person lhs, Person rhs) {
        return lhs.getAge() < rhs.getAge() ? -1 : lhs.getAge() == lhs.getAge() ? 0 : 1;
    }
});

If the ages of two items are equal, how do I compare them using the name instead?

Upvotes: 0

Views: 547

Answers (1)

Tolik Pylypchuk
Tolik Pylypchuk

Reputation: 680

Starting with Java 8, creating a custom Comparator is much easier, and you can compare multiple fields.

You can use the following code:

Comparator.comparing(Person::getAge).thenComparing(Person::getName)

And that's it.

You can use it to sort your collection like this:

Collections.sort(filteredList, Comparator.comparing(Person::getAge).thenComparing(Person::getName))

Upvotes: 2

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