learning base R [book review]

This second edition of an introductory R book was sent to me by the author for a potential CHANCE book review.  As there are many (many) books in the same spirit, the main question behind my reading it (in one go) was on the novelty it brings. The topics Learning Base R covers are

• arithmetics with R
• data structures
• built-in and user-written R functions
• R utilities
• more data structures
• comparison and coercion
• lists and data frames
• resident R datasets
• R interface
• probability calculations in R
• R graphics
• R programming
• simulations
• statistical inference in R
• linear algebra
• use of R packages

within as many short chapters. The style is rather standard, that is, short paragraphs with mostly raw reproductions of line commands and their outcome. Sometimes a whole page long of code examples (if with comments). All in all I feel there are rather too few tables when compared with examples, at least for my own taste. The exercises are mostly short and, while they vary in depth, they show that the book is rather intended for students with some mathematical background (e.g., with a chapter on complex numbers and another one on linear algebra that do not seem immediately relevant for most intended readers). Or more than that, when considering one (of several) exercise (19.30) on the Black-Scholes process that mentions Brownian motion. Possibly less appealing for would-be statisticians.

I also wonder at the pedagogical choice of not including and involving more clearly graphical interfaces like R studio as students are usually not big fans of “old-style” [their wording not mine!] line command languages. For instance, the chapter on packages would have benefited from this perspective. Nothing on Rmarkdown either. Apparently nothing on handling big data, more advanced database manipulation, the related realistic dangers of memory freeze and compulsory reboot, the intricacies of managing different directories and earlier sessions, little on the urgency of avoiding loops (p.233) by vectorial programming, a paradoxically if function being introduced after ifelse, and again not that much on statistics (with density only occurring in exercises).The chapter on customising R graphics may possibly scare the intended reader when considering the all-in-one example of p.193! As we advance though the book, the more advanced examples often are fairly standard programming ones (found in other language manuals) like creating Fibonacci numbers, implementing Eratosthenes sieve, playing the Hanoi Tower game… (At least they remind me of examples read in the language manuals I read as a student.) The simulation chapter could have gone into the one (Chap. 19) on probability calculations, rather than superfluously redefining standard distributions. (Except when defining a random number as a uniformly random number (p.162).)  This chapter also spends an unusual amount of space on linear congruencial pseudo-random generators, while missing to point out the trivia that the randu dataset mentioned twice earlier is actually an outcome from the infamous RANDU Fortran generator. The following section in that chapter is written in such a way that it may give the wrong impression that one can find the analytic solution from repeated Monte Carlo experiments and hence the error. Which is rarely the case, even in finite environments with rational expectations, as one usually does not know of which unit fraction the expectation should be a multiple of. (Remember the Squid Games paradox!) And no mention is made of the prescription of always returning an error estimate along with the numerical approximation. The statistics chapter is obviously more developed, with descriptive statistics, ecdf, but no bootrstap, a t.test curiously applied to the Michelson measurements of the speed of light (how could it be zero?!), ANOVA, regression handled via lm and glm, time series analysis by ARIMA models, which I hope will not be the sole exposure of readers to these concepts.

In conclusion, there is nothing critically wrong with this manual introducing R to newcomers and I would not mind having my undergraduate students reading it (rather than our shorter and home-made handout, polished along the years) before my first mathematical statistics lab. However I do not find it massively innovative in its presentation or choice of concept, even though the most advanced examples are not necessarily standard, and may not appeal to all categories of students.

[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Book Review section in CHANCE.]

COMPUTO, the journal for reproducible statistical research

Computo (latin for calculate, compute, reckon) is a new journal launched by the French statistical society (SFDS) to promote reproducible research in statistics and machine learning by publishing papers with reproducible contributions. Towards this goal, Computo goes beyond classical static publications by including technical advances in literate programming and scientific reporting. The reproducibility of numerical results is a necessary condition for publication in Computo. In particular, submissions must include all necessary data (e.g. via zenodo repositories) and code. For contributions featuring the implementation of methods/algorithms, the quality of the provided code is assessed during the review process. Meaning accepting contributions in the form of notebooks (e.g. Rmarkdown, or Jupyter). This is a 100% free and open-access journal, thanks to the sponsoring of the SFDS. Once a manuscript is accepted, its reviews will be made available on the Computo website. Reviewers can choose to remain anonymous or not. (Towards an even broader reach, we are now considering a partnership with the PCI, following an earlier attempt I did not pursue till its completion…) Computo’s logo has been designed by Loïc Schwaller. And represents the letters of Computo in bytes. Submissions are now open!

ten computer codes that transformed science

In a “Feature” article of 21 January 2021, Nature goes over a poll on “software tools that have had a big impact on the world of science”. Among those,

the Fortran compiler (1957), which is one of the first symbolic languages, developed by IBM. This is the first computer language I learned (in 1982) and one of the two (with SAS) I ever coded on punch cards for the massive computers of INSEE. I quickly and enthusiastically switched to Pascal (and the Apple IIe) the year after and despite an attempt at moving to C, I alas kept the Pascal programming style in my subsequent C codes (until I gave up in the early 2000’s!). Moving to R full time, even though I had been using Splus since a Unix version was produced. Interestingly, a later survey of Nature readers put R at the top of the list of what should have been included!, incidentally including Monte Carlo algorithms into the list (and I did not vote in that poll!),

the fast Fourier transform (1965), co-introduced by John Tukey, but which I never ever used (or at least knowingly!),

arXiv (1991), which was started as an emailed preprint list by Paul Ginsparg at Los Alamos, getting the current name by 1998, and where I only started publishing (or arXiving) in 2007, perhaps because it then sounded difficult to submit a preprint there, perhaps because having a worldwide preprint server sounded more like bother (esp. since we had then to publish our preprints on the local servers) than revolution, perhaps because of a vague worry of being overtaken by others… Anyway, I now see arXiv as the primary outlet for publishing papers, with the possible added features of arXiv-backed journals and Peer Community validations,

the IPython Notebook (2011), by Fernando Pérez, which started by 259 lines of Python code, and turned into Jupyter in 2014. I know nothing about this, but I can relate to the relevance of the project when thinking about Rmarkdown, which I find more and more to be a great way to work on collaborative projects and to teach. And for producing reproducible research. (I do remember writing once a paper in Sweave, but not which one…!)