Java IntStream average() Method

The average() method in Java, part of the java.util.stream.IntStream interface, is used to calculate the average of elements in an IntStream. This method is useful when you need to find the mean value of a sequence of integers.

Table of Contents

1. Introduction
2. average() Method Syntax
3. Understanding average()
4. Examples
   • Basic Usage
   • Using average() with Other Stream Operations
5. Real-World Use Case
6. Conclusion

Introduction

The average() method is a terminal operation that returns an OptionalDouble describing the arithmetic mean of elements in an IntStream. If the stream is empty, it returns an empty OptionalDouble.

average() Method Syntax

The syntax for the average() method is as follows:

OptionalDouble average()

Parameters:

• This method does not take any parameters.

Returns:

• An OptionalDouble describing the average of elements in the stream, or an empty OptionalDouble if the stream is empty.

Throws:

• This method does not throw any exceptions.

Understanding average()

The average() method calculates the arithmetic mean of the elements in an IntStream. The result is wrapped in an OptionalDouble to handle the case where the stream might be empty. If the stream contains elements, the OptionalDouble will contain the average value; otherwise, it will be empty.

Examples

Basic Usage

To demonstrate the basic usage of average(), we will create an IntStream and use average() to calculate the average of its elements.

Example

import java.util.OptionalDouble;
import java.util.stream.IntStream;

public class AverageExample {
    public static void main(String[] args) {
        IntStream intStream = IntStream.of(1, 2, 3, 4, 5);

        // Calculate the average of the elements in the stream
        OptionalDouble average = intStream.average();

        // Print the average if present
        average.ifPresent(System.out::println);
    }
}

Output:

3.0

Using average() with Other Stream Operations

This example shows how to use average() in combination with other stream operations, such as filtering.

Example

import java.util.OptionalDouble;
import java.util.stream.IntStream;

public class AverageWithOtherOperationsExample {
    public static void main(String[] args) {
        IntStream intStream = IntStream.of(1, 2, 3, 4, 5);

        // Filter the elements and calculate the average of the remaining elements
        OptionalDouble average = intStream.filter(n -> n > 2).average();

        // Print the average if present
        average.ifPresent(System.out::println);
    }
}

Output:

4.0

Real-World Use Case

Calculating Average Score

In real-world applications, the average() method can be used to calculate the average score from a stream of student scores.

Example

import java.util.OptionalDouble;
import java.util.stream.IntStream;

public class AverageScoreExample {
    public static void main(String[] args) {
        IntStream scores = IntStream.of(75, 85, 90, 88, 92);

        // Calculate the average score
        OptionalDouble averageScore = scores.average();

        // Print the average score if present
        averageScore.ifPresent(avg -> System.out.println("Average score: " + avg));
    }
}

Output:

Average score: 86.0

Conclusion

The IntStream.average() method is used to calculate the average of elements in a stream. This method is particularly useful for finding the mean value of a sequence of integers. By understanding and using this method, you can efficiently calculate averages in your Java applications.