Book Image

Clojure Data Analysis Cookbook

By : Eric Rochester
Book Image

Clojure Data Analysis Cookbook

By: Eric Rochester

Overview of this book

<p>Data is everywhere and it's increasingly important to be able to gain insights that we can act on. Using Clojure for data analysis and collection, this book will show you how to gain fresh insights and perspectives from your data with an essential collection of practical, structured recipes.<br /><br />"The Clojure Data Analysis Cookbook" presents recipes for every stage of the data analysis process. Whether scraping data off a web page, performing data mining, or creating graphs for the web, this book has something for the task at hand.<br /><br />You'll learn how to acquire data, clean it up, and transform it into useful graphs which can then be analyzed and published to the Internet. Coverage includes advanced topics like processing data concurrently, applying powerful statistical techniques like Bayesian modelling, and even data mining algorithms such as K-means clustering, neural networks, and association rules.</p>
Table of Contents (18 chapters)
Clojure Data Analysis Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Calling R functions from Clojure


R, and the packages that have been developed for it, provide a rich environment for doing statistical computing. To access any of that, however, we'll need to be able to call functions from Clojure. We do this by constructing R expressions as strings, sending them to the R server, and getting the results back. The Rserve Java library helps us convert the results to Java objects that we can access.

Getting ready

We must first complete the Setting up R to talk to Clojure recipe, and have Rserve running. We must also have the Clojure-specific parts of that recipe done and the connection to Rserve made.

How to do it…

Once we have a connection to the Rserver, we can call functions by passing the complete call—function and arguments—to the server as a string and evaluating it. Then we have to pull the results back out.

user=> (map #(.asDouble %) (.. *r-cxn* (eval "qr(c(1,2,3,4,5,6,7))") asList))
(-11.832159566199232 1.0 1.0845154254728517 1.0)

How it works…

To call...