In IBAHCM/RPiR: Reproducible Programming in R

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

General

Keyboard shortcuts:

+-------------+-----------------------------+--------------------------+ | Description | Mac | Windows | +=============+=============================+==========================+ | Run lines | Command + Enter | Ctrl + Enter | | of code | | | +-------------+-----------------------------+--------------------------+ | (Un)comment | Command + Shift + C | Ctrl + Shift + C | | lines of | | | | code | | | +-------------+-----------------------------+--------------------------+ | Insert a | Command + Shift + R | Ctrl + Shift + R | | foldable | | | | comments | | | | section | | | +-------------+-----------------------------+--------------------------+ | Reindent | Command + I | Ctrl + I | | lines of | | | | code | | | +-------------+-----------------------------+--------------------------+ | Reformat | Command + Shift + A | Ctrl + Shift + A | | lines of | | | | code | | | +-------------+-----------------------------+--------------------------+ | Attempt | Tab | Tab | | code | | | | completion | | | +-------------+-----------------------------+--------------------------+ | Clear the | Control + L | Ctrl + L | | console | | | +-------------+-----------------------------+--------------------------+ | Insert an | Alt + - | Alt + - | | assignment | | | | operator, | | | | <- | | | +-------------+-----------------------------+--------------------------+ | Insert a | Command + Shift + M | Ctrl + Shift + M | | pipe | | | | operator, | | | | %>% | | | +-------------+-----------------------------+--------------------------+ | Rename a | Command + Shift + M + Alt | Ctrl + Shift + M + Alt | | variable | | | | in scope | | | +-------------+-----------------------------+--------------------------+

Note: If you are running R 4.1+ you can switch to the native pipe operator, |>. To do this to to Preferences > Code and check the box "Use native pipe operator".

Note also: An easy way to remember the Rename in scope shortcut is Pipe + Alt.
To encapsulate text in quotes or brackets, highlight the text, then type " or (.
To generate code used to recreate an object:

r x <- data.frame(a = 2, b = 4) y <- dput(x) y

Writing loops

To generate a sequence of numbers to iterate over:

r data <- c(1, 33, 100, 102) seq_along(data)

alternatively:

r data <- data.frame(a = 1:3, b = 4:6) seq_len(nrow(data))
To print a counter to the console:

r for (i in 1:3) { cat("\n", i) }

Note: \n moves the "print head" to a new line, whereas \r will move it back to the start of the same line.

Command history

Keyboard shortcuts (from the console):

+------------------------+----------------------+--------------------+ | Description | Mac | Windows | +========================+======================+====================+ | Cycle through previous | Up arrow | | | commands | | | +------------------------+----------------------+--------------------+ | Show previous commands | Command + Up arrow | | +------------------------+----------------------+--------------------+ | Auto-complete commands | Control + R | |
| (from previous) | | | +------------------------+----------------------+--------------------+

Writing functions

To generate a function skeleton as a code snippet, type fun then hit tab and return (to select the snippet):

```r name <- function(variables) {

} ```

Keep hitting tab to move from name to variables to the body of the function.
Function extraction -- to turn a chunk of code into a function, highlight a chunk of code, then press Control + Alt + X on Mac (or Windows) and enter a suitable function name when prompted. In doing so, this:

r x * y

turns into this:

r multiply <- function(x, y) { x * y }

Note: You can make your own custom code snippets in Tools > Global Options > Code and clicking Edit Snippets in the Snippets section.

Graphics

To generate a sequence of evenly spaced values (useful when manually defining axis breaks in ggplot2):

r x <- c(0, 0.001, 1, 8) pretty(x)
To list the names of built in colours:

r x <- colors() head(x)

Packages

Keyboard shortcuts:

+------------------+-----------------------+------------------------+ | Description | Mac | Windows | +==================+=======================+========================+ | Document package | Command + Shift + D | Ctrl + Shift + D | +------------------+-----------------------+------------------------+

Search

To select the path of a file in your current directory, hit Tab inside of:

r ""
To locate files relative to your project root, after installing the here package:

r library(here) here("R", "assert_no_globals.R")
Keyboard shortcuts:

+-------------------------+-----------------------+--------------------+ | Description | Mac | Windows | +=========================+=======================+====================+ | Find files / functions | Control + . | Ctrl + . | +-------------------------+-----------------------+--------------------+ | Search all files in a | Command + Shift + F | | | directory / project | | | +-------------------------+-----------------------+--------------------+

Miscellaneous

Keyboard shortcuts:

+-----------------------+-------------------------+--------------------+ | Description | Mac | Windows | +=======================+=========================+====================+ | Show command palette | Command + Shift + P | Ctrl + Shift + P | +-----------------------+-------------------------+--------------------+ | Keyboard shortcut | Alt + Shift + K | | | reference | | | +-----------------------+-------------------------+--------------------+ | Zoom in on an RStudio | Control + Shift + 1-4 | | | panel | | | +-----------------------+-------------------------+--------------------+
To find RMarkdown cheat sheets in RStudio, go to Help > Cheat Sheets > R Markdown Reference Guide. You can also find cheat sheets for dplyr, ggplot2, and devtools here.
To automatically load packages on startup / restarting R:
1. Create an .Rprofile file in your project root
2. Fill it with anything you want loaded on startup
Note that you should not use this to load in packages used in your analyses, such as dplyr or ggplot2.

A useful example might be:

r library(devtools, quietly = TRUE)

However, you can also populate it with any helper functions you might regularly use, or even R fortunes.
To generate an R fortune, after installing fortunes:

r fortune()