Book Image

Mastering Apache Spark 2.x - Second Edition

Book Image

Mastering Apache Spark 2.x - Second Edition

Overview of this book

Apache Spark is an in-memory, cluster-based Big Data processing system that provides a wide range of functionalities such as graph processing, machine learning, stream processing, and more. This book will take your knowledge of Apache Spark to the next level by teaching you how to expand Spark’s functionality and build your data flows and machine/deep learning programs on top of the platform. The book starts with a quick overview of the Apache Spark ecosystem, and introduces you to the new features and capabilities in Apache Spark 2.x. You will then work with the different modules in Apache Spark such as interactive querying with Spark SQL, using DataFrames and DataSets effectively, streaming analytics with Spark Streaming, and performing machine learning and deep learning on Spark using MLlib and external tools such as H20 and Deeplearning4j. The book also contains chapters on efficient graph processing, memory management and using Apache Spark on the cloud. By the end of this book, you will have all the necessary information to master Apache Spark, and use it efficiently for Big Data processing and analytics.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
10
Deep Learning on Apache Spark with DeepLearning4j and H2O

User-defined functions


In order to create user-defined functions in Scala, we need to examine our data in the previous Dataset. We will use the age property on the client entries in the previously introduced client.json. We plan to create an UDF that will enumerate the age column. This will be useful if we need to use the data for machine learning as a lesser number of different values is sometimes useful. This process is also called binning or categorization. This is the JSON file with the age property added:

Now let's define a Scala enumeration that converts ages into age range codes. If we use this enumeration among all our relations, we can ensure consistent and proper coding of these ranges:

 object AgeRange extends Enumeration {
    val Zero, Ten, Twenty, Thirty, Fourty, Fifty, Sixty, Seventy, Eighty, Ninety, HundretPlus = Value
    def getAgeRange(age: Integer) = {
      age match {
        case age if 0 until 10 contains age => Zero
        case age if 11 until 20 contains age ...