10 Steps to Understanding Data Structures in Haskell

(Skip to the steps)

Last year I completed Advent of Code, which presented a lot of interesting algorithmic challenges. One thing these problems really forced me to do was focus more clearly on using appropriate data structures, often going beyond the basics.

And looking back on that, it occurred to me that I hadn't really seen many tutorials on Haskell structures beyond lists and maps. Nor in fact, had I thought to write any myself! I've touched on sequences and arrays, but usually in the context of another topic, rather than focusing on the structure itself.

So after thinking about it, I decided it seemed worthwhile to start doing some material providing an overview on all the different structures you can use in Haskell. So data structures will be our "blog topic" starting in this month of July, and probably actually going into August. I'll be adding these overviews in a permanent series, so each blog post over the next few Mondays and Thursdays will link to the newest installment in that series.

But even beyond providing a basic overview of each type, I thought it would be helpful to come up with a process for learning new data structures - a process I could apply to learning any structure in any langugage. Going to the relevant API page can always be a little overwhelming. Where do you start? Which functions do you actually need?

So I made a list of the 10 steps you should take when learning the API for a data structure in a new language. The first of these have to do with reminding yourself what the structure is used for. Then you get down to the most important actions to get yourself started using that structure in code.

The 10 Steps

1. What operations does it support most efficiently? (What is it good at?)
2. What is it not as good at?
3. How many parameters does the type use and what are their constraints.
4. How do I initialize the structure?
5. How do I get the size of the structure?
6. How do I add items to the structure?
7. How do I access (or get) elements from the structure?
8. If possible, how do I delete elements from the structure?
9. How do I combine two of these structures?
10. How should I import the functions of this structure?

Each part of the series will run through these steps for a new structure, focusing on the basic API functions you'll need to know. To see my first try at using this approach where I go over the basic list type, head over to the first part of the series! As I update the series with more advanced structures I'll add more links to this post.

If you want to quickly see all the APIs for the structures we'll be covering, head to our eBooks page and download the FREE Data Structures at a Glance eBook!