Cheatsheet - R

R Cheatsheet

Sources:

• **

title: Contents 
style: nestedList # TOC style (nestedList|inlineFirstLevel)
minLevel: 1 # Include headings from the specified level
maxLevel: 4 # Include headings up to the specified level
includeLinks: true # Make headings clickable
debugInConsole: false # Print debug info in Obsidian console

Package Management

• Installation:

install.packages("dplyr")
 
pak::pak("dplyr")

R CMD INSTALL /path/to/pkg

cd /path/to/project/source
Rscript -e "install.packages('$PWD', repos=NULL, type='source')"

• Installed Package Metadata:

packageVersion("dplyr")
packageDescription("dplyr")
 
sessioninfo()

• Print list of functions in package:

ls('package:dplyr')

• Unload/Detach Library:

detach('package:dplyr', unload = TRUE)

Store Variable Inside Package Environment:

.pkgenv <- new.env()
 
set.workdir <- function(path) {
  assign('WORKDIR', path, envir=.pkgenv)
}
 
get.workdir <- function() {
  get('WORKDIR', envir=.AchiaEnv)
}

Scripting

Use this first line for R scripts:

#!/usr/bin/env Rscript

Ask for user input in Rscript:

cat('\n[Press Enter]\n')
foo <- scan("stdin", character(), n=1, nlines=1, quiet=TRUE)

Getting help

Get help about any R function or structure:

# documentation of the `rle` function
?rle

# documentation of the `read.csv` function
?read.csv

Objects in memory

# list objects in memory
ls()

# delete objects from memory
rm('variablename')

# delete all objects
rm(list = ls())

Navigating in the filesystem

# current working directory
getwd()

# change to another directory
setwd('/path/to/somewhere/else')

Extracting subsets from data frames

# these are the same
subset(airquality, Month == 5)
subset(airquality, airquality[,'Month'] == 5)
subset(airquality, airquality[,5] == 5)

Misc

Modulo operator:

# 5 mod 3 is 2
# 3 mod 5 is 3
i %% n

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Appendix

Note created on 2024-03-28 and last modified on 2024-03-28.

Backlinks

LIST FROM [[Cheatsheet - R]] AND -"CHANGELOG" AND -"04-RESOURCES/Cheatsheets/Cheatsheet - R"

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