How to change size of an array-list to match the size of a given array-list in JAVA

Question

I have two array lists which in different sizes, so I want to make the array list which is larger in size equal to smaller one size.

Double[] x = {
  14.2, 16.4, 11.9, 15.2, 18.5, 22.1, 19.4, 25.1, 23.4, 18.1, 22.6, 17.2
};
Double[] y = {
  17.5, 14.2, 12.2, 16.0, 19.3
};

ArrayList<Double> aListX = new ArrayList<>(Arrays.asList(x));
ArrayList<Double> aListY = new ArrayList<>(Arrays.asList(y));

I want ArrayList aListX as the same size as an ArrayList aListY

Result:

aListX.size() = 5

Answer 1

If you can declare the list as a List instead of an ArrayList

List<Double> aListX

then you can do

aListX = aListX.subList(0, aListY.size());

Answer 2

This is the way to do it :)

    aListX = new ArrayList<>(aListX.subList(0, aListY.size()));

Answer 3

您可以使用迭代器删除第5个索引之后的元素

Iterator iterate = aListX.iterator();
int index = 0;
while (iterate.hasNext()) {
    iterate.next();
    if (index >= aListY.size()) {
        iterate.remove();
    }
    ++index;
}