JuniorTheoryCommon

What does the program print?

JAVA

import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> xs = List.of(1, 2, 3, 4, 5);
        List<Integer> r = xs.stream()
            .filter(x -> x % 2 == 1)
            .map(x -> x * 10)
            .toList();
        System.out.println(r);
    }
}

[10, 30, 50]

Expecting [20, 40]: filter keeps the elements for which the predicate returns true, here the odd ones, and drops the rest.
Expecting map to see all five numbers: each step works on the output of the step before it, so map gets only 1, 3 and 5.

What does System.out.println(xs) print after this pipeline, and why?
How do you get the sum of these numbers instead of a list?

Back to questions Open topic in roadmap →Answer it yourself — Quiz

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JuniorTheoryCommon

What does the program print?

JAVA

import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Integer> xs = List.of(1, 2, 3, 4, 5);
        List<Integer> r = xs.stream()
            .filter(x -> x % 2 == 1)
            .map(x -> x * 10)
            .toList();
        System.out.println(r);
    }
}

[10, 30, 50]

Expecting [20, 40]: filter keeps the elements for which the predicate returns true, here the odd ones, and drops the rest.
Expecting map to see all five numbers: each step works on the output of the step before it, so map gets only 1, 3 and 5.

What does System.out.println(xs) print after this pipeline, and why?
How do you get the sum of these numbers instead of a list?

Back to questions Open topic in roadmap →Answer it yourself — Quiz