Book Image

Apache Spark for Data Science Cookbook

By : Padma Priya Chitturi
Book Image

Apache Spark for Data Science Cookbook

By: Padma Priya Chitturi

Overview of this book

Spark has emerged as the most promising big data analytics engine for data science professionals. The true power and value of Apache Spark lies in its ability to execute data science tasks with speed and accuracy. Spark’s selling point is that it combines ETL, batch analytics, real-time stream analysis, machine learning, graph processing, and visualizations. It lets you tackle the complexities that come with raw unstructured data sets with ease. This guide will get you comfortable and confident performing data science tasks with Spark. You will learn about implementations including distributed deep learning, numerical computing, and scalable machine learning. You will be shown effective solutions to problematic concepts in data science using Spark’s data science libraries such as MLLib, Pandas, NumPy, SciPy, and more. These simple and efficient recipes will show you how to implement algorithms and optimize your work.
Table of Contents (17 chapters)
Apache Spark for Data Science Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Applying user-defined functions in SparkR


In this recipe we'll see how to apply the functions such as dapply, gapply and lapply over the Spark DataFrame.

Getting ready

To step through this recipe, you will need a running Spark Cluster either in pseudo distributed mode or in one of the distributed modes that is, standalone, YARN, or Mesos. Also, install RStudio. Please refer the Installing R recipe for details on the installation of R and Creating SparkR DataFrames recipe to get acquainted with the creation of DataFrames from a variety of data sources.

How to do it…

In this recipe, we'll see how to apply the user defined functions available as of Spark 2.0.2.

  1. Here is the code which applies dapply on the Spark DataFrame.

          schema <- structType(structField("eruptions", "double"),
          structField("waiting", "double"), structField("waiting_secs",  
          "double"))
          df1 <- dapply(df, function(x) { x <- cbind(x, x$waiting * 60) },   
          schema)
         ...