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

Querying data with Cascalog


In the Distributed processing with Cascalog and Hadoop recipe, we started looking at how to query data in Cascalog with a couple of small examples. However, Cascalog's query language is much more powerful than we saw there. We'll dive in further in this recipe and start looking at some of the logical predicates available. Recipes later in this chapter will have still more examples of querying with Cascalog.

Getting ready

For this recipe, we'll need the project.clj file dependencies and imports from the Distributed processing with Cascalog and Hadoop recipe. We'll also use the data from that recipe: the sequences of information about the companions and actors from the British television program, Doctor Who.

How to do it…

  1. For the first example, we'll get the first five actors who played the doctor.

    (?<- (stdout) [?n ?actor ?period]
         (actor ?n ?actor ?period) (<= ?n 5))
    …
    RESULTS
    -----------------------
    1       William Hartnell        1963–66
    2       Patrick...