Question

I am new to Java, I want to store an array of pair of doubles. My code looks like this:

import java.util.ArrayList;
import java.util.Map.Entry;

List<Entry<Double, Double>> values = new ArrayList<>();
Entry<Double, Double> pair;
// set pair values:
// pair.setKey(0.5); // this method does not exists
// pair.setValue(3.6);
values.add(pair);

How can I initialize the pair variable?
Is there a better structure to store my array of pair of doubles?

Answer 1

Create your own class to represent a pair and add a constructor that takes two arguments:

public class MyPair
{
    private final Double key;
    private final Double value;

    public MyPair(Double aKey, Double aValue)
    {
        key   = aKey;
        value = aValue;
    }

    public Double key()   { return key; }
    public Double value() { return value; }
}

See this answer for reasons why a Pair does not exist in Java: What is the equivalent of the C++ Pair<L,R> in Java?