JuniorTheoryCommon

What does the program print?

JAVA

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> xs = new ArrayList<>();
        xs.add(10);
        xs.add(20);
        xs.add(30);
        xs.remove(1);
        System.out.println(xs);
    }
}

[10, 30]

Expecting [10, 20, 30]: remove(1) with an int removes by index, not by value; to remove the number 1, call remove(Integer.valueOf(1)).
Expecting [20, 30]: list indices start at 0, as in arrays, so index 1 is the second element, 20.

How do you remove the value 20 instead of the element at an index?
What does remove(Object) return when the value is not in the list?

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JuniorTheoryCommon

What does the program print?

JAVA

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> xs = new ArrayList<>();
        xs.add(10);
        xs.add(20);
        xs.add(30);
        xs.remove(1);
        System.out.println(xs);
    }
}

[10, 30]

Expecting [10, 20, 30]: remove(1) with an int removes by index, not by value; to remove the number 1, call remove(Integer.valueOf(1)).
Expecting [20, 30]: list indices start at 0, as in arrays, so index 1 is the second element, 20.

How do you remove the value 20 instead of the element at an index?
What does remove(Object) return when the value is not in the list?

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