There's not a lot of data analysis that we can do without data, so the first step in any project is evaluating what data we have and what we need. And once we have some idea of what we'll need, we have to figure out how to get it.

Many of the recipes in this chapter and in this book use Incanter (http://incanter.org/) to import the data and target Incanter datasets. Incanter is a library for doing statistical analysis and graphics in Clojure, similar to R. Incanter may not be suitable for every task—later we'll use the Weka library for clustering and machine learning—but it is still an important part of our toolkit for doing data analysis in Clojure. This chapter has a collection of recipes for gathering data and making it accessible to Clojure. For the very first recipe, we'll look at how to start a new project. We'll start with very simple formats like comma-separated values (CSV) and move into reading data from relational databases using JDBC. Then we'll examine more complicated data sources, such as web scraping and linked data (RDF).