Day 04: `here::here()`

Begin your journey to project-oriented-workflow enlightenment by using here::here() to build file paths.

Published

December 4, 2022

The titular function of the here package (Müller 2020), here::here(), hasn’t exactly been slept on. Among other things, it’s garnered an excellent illustration by Allison Horst (below), and an ode by Jenny Bryan.

A cartoon showing two paths side-by-side. On the left is a scary spooky forest, with spiderwebs and gnarled trees, with file paths written on the branches like"~/mmm/nope.csv" and "setwd("/haha/good/luck/")", with a scared looking cute fuzzy monster running out of it. On the right is a bright, colorful path with flowers, rainbow and sunshine, with signs saying "here!" and "it's all right here!" A monster facing away from us in a backpack and walking stick is looking toward the right path. Stylized text reads "here: find your path." — Artwork by @allison_horst

Why all the fuss?

here() is one of the keys to a collaborative, project-oriented workflow. Rather than using setwd() (which usually involves an absolute path to a location on a single user’s machine), you can use here() to build file paths that are relative to the project root.

For example, when reading in data for a project, my script usually looks something like the following:

read_csv(here::here("data", "my_data.csv"))

Since I do almost all of my work in projects with .Rproj files, this means that the data I’m reading is in a subfolder of my project called “data”, and the file is “my_data.csv”.

If you’re not an .Rproj user, here() has a hierarchy of heuristics it uses to determine the project root, including checking for the presence of a file named .here. For more detail, Jenny Bryan’s ode contains an excellent section on the fine print.

References

Müller, Kirill. 2020. here: A Simpler Way to Find Your Files. https://here.r-lib.org.