I’ve just finished a slideshow about a preliminary translation of a simulation of the UK economy from Python into R. The simulation is the one I’ve been blogging about in recent posts. It’s a “microeconomic” model, meaning that it simulates at the level of individual people. In ... [Read more...]

One out of quite a lot of confusing things about R is that it has two kinds of conditional expression. There’s ifelse(); and there’s the if statement. It’s important to know which one to use, as I found when trying to write a conditional expression that chose ... [Read more...]

I use R on a range of Windows machines. Often, I’ll only use these once, and they won’t already have R. So I want to carry an installation with me. So I decided to install R on a memory stick. Installing R itself worked, once I’d changed ... [Read more...]

Most people have a job. Some don’t. And a few have more than one. I’ve mentioned before that our economic model works on data about British households, gathered from surveys such as the Family Resources Survey. Each collection of data is a year long, and contains a file ... [Read more...]

Here’s another innocent-eye exploration, this time about the Tidyverse’s summarise() function. I’d been combining data tables by nesting and joining them, which gave me a tibble with nested tibbles in. I wanted to check the sizes of these inner tibbles, by mapping nrow() over the columns containing ... [Read more...]

I spied a strange thing with my innocent eye. I was testing spread_to_list, the function I wrote about in “How Best to Convert a Names-Values Tibble to a Named List?”. One of my tests passed it a zero-row tibble, expecting that the result would be a zero-element list: ... [Read more...]

Consider this tibble: vat_rates [Read more...]

Here, in the spirit of my “Experiments with by_row()” post, are some experiments in writing and timing a function spread_to_list that converts a two-column tibble such as: x 1 y 2 z 3 t 4 to a named list: list( x=1, y=2, z=3, t=4 ) I need this for processing the parameter ... [Read more...]

I’ve been experimenting with by_row() from the R purrrlyr package. It’s a function that maps over the rows of a data frame, which I thought might be handy for processing our economic model’s parameter files. I didn’t find the documentation for by_row() told me ... [Read more...]

In “Abstract Data Types and the Uniform Referent Principle I: why Douglas T. Ross would hate nest(), unnest(), gather() and spread()”, I explained why the notation for interfacing to a data structure should be independent of that structure’s representation. R programmers honour this principle in the same way that ... [Read more...]

“What’s the Uniform Referent Principle?” my colleague asked me on reading my last post. I think I first came across it in Jean Sammet’s famous book Programming Languages: History and Fundamentals. In a description of Douglas Ross’s AED-0 language, she pointed out a feature that she thought ... [Read more...]

I’ve been experimenting with the Tidyverse’s nest function, because it may be useful when, for example, using households together with benefit units. Below are some thoughts that I first posted as a comment to Hadley Wickham’s blog entry “tidyr 0.4.0”. More on this in future posts. First, this ... [Read more...]