As a learning exercise, I decided to translate examples from the book, From Python to NumPy, into R and Chez Scheme. This post describes the random walk example from Chapter 2. All of the code is in this repository so I will only highlight a few pieces of code below. For context, I am a long-time R programmer who only periodically pokes at Python and dabbles in Scheme for fun. Because performance is the primary motivation of vectorizing code with NumPy in Python, I will be loosely comparing timings between Python, R, and Chez Scheme. Take these timings with a large grain of salt. I don't know how comparable the different timings are.

As a learning exercise, I wrote a dataframe library for Scheme. Because I was learning Scheme while I wrote dataframe, I did not prioritize performance. However, as I've tried to use the dataframe library (exploratory data analysis, spam simulation, gapminder), I've encountered performance pitfalls that make dataframe largely unusable for datasets with more than a few thousand rows. I have a rough idea of where the bottlenecks are, but I thought it would be a useful to take a step back and visualize the dataframe procedures as a network graph.

The stochastic logistic population model described in this blog post has become my default exercise when I'm exploring a new programming language (Racket, F#, Rust). I ended that Rust post by noting that I was interested in Rust as a modern alternative for scientific computing and thought it would be a good learning exercise to re-write small legacy Fortran programs in Rust. In the process of looking for Fortran programs to translate to Rust, though, I found myself becoming more interested in the idea of learning Fortran than Rust, particularly after learning about the efforts to improve the tooling around Fortran (e.g., here and here). So, here we are...exploring Fortran via the stochastic population model exercise.

I keep my eye out for blog posts illustrating data analysis tasks in R that I can use to test the functionality of my chez-stats and dataframe libraries for Chez Scheme [1]. A post comparing pandas (Python) and dplyr (R) in a basic analysis of the gapminder dataset provides a nice little test case. In this post, I will also include base R code used to accomplish the same tasks as a contrast to both the Scheme code and the dplyr code from the other post.

I recently came across this blog post on writing simple test programs in different programming languages as a way to get a feel for a language. At the bottom of the post, there were links to articles on implementations of a number guessing game in 13 different languages, including Fortran. I was curious about the Fortran example because I've been interested in learning a little Fortran after hearing about efforts to improve the tooling around Fortran (e.g., here and here). Well, the Fortran example was written in Fortran 77 so I decided that re-writing it in modern Fortran would be a nice little exercise.

I learned a lot about Scheme by writing a few Chez Scheme libraries and I expect that there is more to learn by trying to use those libraries (e.g., EDA in Chez Scheme). A blog post about a stochastic simulation of spam comments in R caught my eye as an interesting example to test my chez-stats and dataframe libraries.

As I spent a little time learning F# over the last few months, I found that it wasn't holding my attention. My interest in F# was based on the idea that I could write more robust code (via static typing) than in R and that I could more easily turn that code into web or desktop applications. I still think that F# could be a valuable tool to add to my toolbox, but I encountered just enough friction that I wasn't having fun with it. My primary point of frustration is that so much material for learning F# assumes that you already know C# and .NET. Plus, the roll out of .NET 5 and F# 5 this fall, while exciting, creates a period of increased confusion for beginners.

In three previous posts, I wrote about different programming languages that I have considered learning. I mentioned about 15 different languages in those posts. F# was not on the list. Because my background is in R, I thought I was better off sticking to learning dynamically typed languages at this point. Moreover, I hold a longstanding bias against Microsoft and Windows and that bias was easy to transfer to F#.

When I started learning Scheme, I took the common approach of learning a new language by implementing features from familiar languages (namely R). That approach sent me down the path of writing the chez-stats and dataframe libraries and porting gnuplot-pipe from Chicken to Chez Scheme. Those three libraries now allow me to conduct simple exploratory data analysis (EDA) in Chez Scheme that should be feel relatively familiar to R programmers. In this post, I will work through a simple example, which mostly serves to reinforce how much better suited R is for these types of tasks.

This post is part of a series on the dataframe library for Chez Scheme. In this post, I will contrast the dataframe library with functions from base R and the dplyr package for modifying and aggregating dataframes.