Book Image

Spark for Data Science

By : Srinivas Duvvuri, Bikramaditya Singhal
Book Image

Spark for Data Science

By: Srinivas Duvvuri, Bikramaditya Singhal

Overview of this book

This is the era of Big Data. The words ‘Big Data’ implies big innovation and enables a competitive advantage for businesses. Apache Spark was designed to perform Big Data analytics at scale, and so Spark is equipped with the necessary algorithms and supports multiple programming languages. Whether you are a technologist, a data scientist, or a beginner to Big Data analytics, this book will provide you with all the skills necessary to perform statistical data analysis, data visualization, predictive modeling, and build scalable data products or solutions using Python, Scala, and R. With ample case studies and real-world examples, Spark for Data Science will help you ensure the successful execution of your data science projects.
Table of Contents (18 chapters)
Spark for Data Science
Credits
Foreword
About the Authors
About the Reviewers
www.PacktPub.com
Preface

SparkR DataFrames


In this section, we try out some useful, commonly used operations. First, we try out the traditional R/dplyr operations and then show equivalent operations using the SparkR API:

> //Open the R shell and NOT SparkR shell  
> library(dplyr,warn.conflicts=FALSE)  //Load dplyr first 
//Perform a common, useful operation  
> iris %>%               
+   group_by(Species) %>% +   summarise(avg_length = mean(Sepal.Length),  
+             avg_width = mean(Sepal.Width)) %>% +   arrange(desc(avg_length)) 
Source: local data frame [3 x 3] 
     Species avg_length avg_width 
      (fctr)      (dbl)     (dbl) 
1  virginica      6.588     2.974 
2 versicolor      5.936     2.770 
3     setosa      5.006     3.428 
 
//Remove from R environment 
> detach("package:dplyr",unload=TRUE) 

This operation is very similar to the SQL group and is followed by order. Its equivalent implementation in SparkR is also very similar to the dplyr example. Look at the following example...