Java - round ArrayList elements to two decimal places

In this article, we would like to show you how to round ArrayList elements to two decimal places in Java.

Quick solution:

for (int i = 0; i < myArrayList.size(); i++) {
    double newValue = (double) Math.round(myArrayList.get(i) * 100d) / 100d;
    myArrayList.set(i, newValue);
}

or

for (Double item : myArrayList) {
    double newValue = (double) Math.round(item * 100d) / 100d;
    myArrayList.set(myArrayList.indexOf(item), newValue);
}

Practical examples

Example 1

In this example, we loop through the numbers ArrayList using for loop and round each element using Math.round() method.

package arraylistOperations;

import java.util.*;

public class Example {

    public static void main(String[] args) {
        List<Double> numbers = new ArrayList<>() {{
            add(1.123456);
            add(2.123456);
            add(3.123456);
        }};

        for (int i = 0; i < numbers.size(); i++) {
            double newValue = (double) Math.round(numbers.get(i) * 100d) / 100d;
            numbers.set(i, newValue);
        }

        System.out.println(numbers);  // [1.12, 2.12, 3.12]
    }
}

Output:

[1.12, 2.12, 3.12]

Example 2

In this example, we loop through the numbers ArrayList using for-each loop and round each element using Math.round() method.

import java.util.*;

public class Example {

    public static void main(String[] args) {
        List<Double> numbers = new ArrayList<>() {{
            add(1.123456);
            add(2.123456);
            add(3.123456);
        }};

        for (Double number : numbers) {
            double newValue = (double) Math.round(number * 100d) / 100d;
            numbers.set(numbers.indexOf(number), newValue);
        }

        System.out.println(numbers);  // [1.12, 2.12, 3.12]
    }
}

Output:

[1.12, 2.12, 3.12]

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