Java: Data Science Made Easy

Using Java 8 techniques to find mean

Java 8 provided additional capabilities with the introduction of optional classes. We are going to use the OptionalDouble class in conjunction with the Arrays class's stream method in this example. We will use the same array of doubles we used in the previous example to create an OptionalDouble object. If any of the numbers in the array, or the sum of the numbers in the array, is not a real number, the value of the OptionalDouble object will also not be a real number:

OptionalDouble mean = Arrays.stream(testData).average(); 

We use the isPresent method to determine whether we calculated a valid number for our mean. If we do not get a good result, the isPresent method will return false and we can handle ...