Some thoughts on checking the R session

There is an ancient saying. Okay, well, now that I think about it maybe it’s not so ancient: it’s only been around since 2017 or thereabouts. And actually it’s more of kind of friendly warning than it is a saying. And really it’s only used by a weird group of people who write R scripts and spend too much time on the internet, and I don’t know if that’s wide enough usage to justify such a melodramatic opening. But nevertheless, the warning is real and it goes like this: If your R script begins with rm(list=ls()), Jenny Bryan will come to your office and set your laptop on fire. Among the wizened sages and those young folks who have read the old lore, this warning will be met with much nodding and its deep wisdom will need no further explanation. For in such company it is known that Jenny Bryan is not a malicious spirit who delights in the sight of laptops burning in the twilight, but is instead a kind and gentle teacher who wants you to understand the risks you are taking if you treat…