Install R packages

• from CRAN, 14,925 packages, up to 9/17/2019.

install.packages("mclust")

• from Bioconductor: 1,741 packages, 9/17/2019.

## try http:// if https:// URLs are not supported
if (!requireNamespace("BiocManager", quietly = TRUE))
    install.packages("BiocManager")

BiocManager::install("impute")

• .gz.tar zipped file.

install.packages("mclust_5.4.7.tar",repos=NULL,type="source")

• package folder.

# in R: 
system("R CMD INSTALL mclust")
#command line: R CMD INSTALL mclust

• github.

library(devtools)
install_github("cran/mclust")

Why R package

• Share with others, if your code is in a package, any R user can easily download it, install it and learn how to use it.
• It is about saving yourself time. Organizing code in a package makes your life easier because packages come with conventions.

Basic structure of an R Package

• Using R survival package as an example:
  • DESCRIPTION: metadata, basic information, dependency…
  • NAMESPACE: control the imported and exported objects.
  • R: R code
  • man: manual
  • src: other language (c, java…)
  • test: test validity of your functions
  • vignettes: an overall description of your package
  • ToDo: to do list

Play with survival package

• library a package

library(survival)

• help file about the package

help(package = 'survival')

• help file about one function

?coxph

• check out vignettes

browseVignettes("survival")

Structure of R package

• R/: the most important directory is R/
• DESCRIPTION: basic information, dependency.
• Documentation: if you want other people (including future-you!) to understand how to use the functions in your package, you’ll need to document them.
• Vignettes: function documentation describes the nit-picky details of every function in your package.They’re long-form documents that show how to combine multiple parts of your package to solve real problems.
• Tests: to ensure your package works as designed (and continues to work as you make changes), it’s essential to write unit tests which define correct behaviour, and alert you when functions break.
• Namespace: to play nicely with others, your package needs to define what functions it makes available to other packages and what functions it requires from other packages.
• data/: this directory allows you to include data with your package.
• src/: other programming languages.

DESCRIPTION

The job of the DESCRIPTION file is to store important metadata about your package. Every package must have a DESCRIPTION. In fact, it’s the defining feature of a package.

• LazyLoad, if yes delays the loading of functions until they are required.
• Title and description.
• Author: who are you.
• Dependencies.
• License.
• Version.

DESCRIPTION License

• GPL-2/GPL-3: anyone who distributes modified versions of your code (derivative works) must also make the source code
  • open source,
  • GPL-compatible.
• MIT: This is a simple and permissive license.
  • They are extremely short and essentially say “do whatever you want with this, just don’t sue me.”
• CC0. It relinquishes all your rights on the code and data so that it can be freely used by anyone for any purpose.
• Apache:
  • “do whatever you want with this, just don’t sue me” but does so with many more words
  • Contains patent license and retaliation clause to prevent patents from encumbering the software project
• Many others

DESCRIPTION Version

Formally, an R package version is a sequence of at least two integers separated by either . or -. For example, 1.0 and 0.9.1-10 are valid versions, but 1 or 1.0-devel are not.

• A released version number consists of three numbers, ... For version number 1.9.2, 1 is the major number, 9 is the minor number, and 2 is the patch number. Never use versions like 1.0, instead always spell out the three components, 1.0.0.

• An in-development package has a fourth component: the development version. This should start at 9000. For example, the first version of the package should be 0.0.0.9000.

The namespace file in R package

• Specifies which functions will be visible to users.
• Specifies which functions are internal funciton, for which you don’t want the users to see and use.
• Specifies how to interaction with other programming language (e.g., c++)
• Specifies how to your package depends on other packages
• Don’t need to revise the namespace file, will be managed by devtools.

Namespace

• :: to specify namespace

base::dim

• Namespace protect the internal functions being overwritten by functions from other packages/global environment.

nrow
dim(mtcars)
dim <- function(x) c(1, 1)
dim(mtcars)
nrow(mtcars)

Man (for manual)

• Documentation is one of the most important aspects of a good package. Without it, users won’t know how to use your package.
• Documentation is also useful for future-you (so you remember what your functions were supposed to do), and for developers extending your package.
• R provides a standard way of documenting the objects in a package: you write .Rd files in the man/ directory. These files use a custom syntax, loosely based on LaTeX, and are rendered to HTML, plain text and pdf for viewing.

Devtools, starting from sketches.

Red color indicates essential steps

1. usethis::create_package() create an new R package
2. Copy your R code in inside R folder
3. formatR::tidy_dir() clean up the code
4. Add documentation in R code
5. devtools::document() generate R documentation
6. usethis::use_data() prepare external data
7. usethis::use_testthat() prepare test functions
8. devtools::test() preform test
9. usethis::use_vignette() generate vignettes
10. devtools::check() check the package
11. devtools::build() build the package
12. devtools::install() install the package
13. others

1. devtools::create() create an new R package

## set working directory to be Desktop
WD <- '~/Desktop'
setwd(WD)

usethis::create_package("GatorPKG", open = FALSE) ## open = FALSE will prevent R open a new R studio session.
WD2 <- '~/Desktop/GatorPKG'
setwd(WD2)

2. Copy your R code in inside R folder

• f.R

##' @export
f <- function(x, y) x + y

• g.R

##' @export
g <- function(x, y) x - y

• h.R

##' @export
h <- function(x, y) f(x,y) * g(x,y)

• all.R

##' @export
all <- function(x, y){
  f0 <- f(x,y)
  g0 <- g(x,y)
  h0 <- h(x,y)
  list(f=f0, g=g0, h=h0)
}

3. formatR::tidy dir() clean up the code

setwd(WD2)
## make the code neat
formatR::tidy_dir("R")

4. Add documentation in R code

• f.R

##' Add up two numbers (Description)
##'
##' We want to add up two numbers, blalala... (Details)
##' @title add two numbers
##' @param x first number
##' @param y second number
##' @return sum of two numbers
##' @author Caleb
##' @export
##' @examples
##' f(1,2)
f <- function(x, y) x + y

• g.R

##' Subtract two numbers (Description)
##'
##' We want to Subtract two numbers, blalala... (Details)
##' @title Subtract two numbers
##' @param x first number
##' @param y second number
##' @return x - y
##' @author Caleb
##' @export
##' @examples
##' g(2,1)
g <- function(x, y) x - y

• h.R

##' Complex operations on two numbers (Description)
##'
##' We want to do some complex operations on two numbers, blalala... (Details)
##' @title Very complex operation of two numbers
##' @param x first number
##' @param y second number
##' @return (x - y)(x + y)
##' @author Caleb
##' @export
##' @examples
##' h(3,2)
h <- function(x, y) f(x,y) * g(x,y)

• all.R

##' Return f,g,h (Description)
##'
##' We want to return f,g,h , blalala... (Details)
##' @title return all
##' @param x first number
##' @param y second number
##' @return A list of f, g, and h.
##' \item{f}{Results for adding}
##' \item{g}{Results for subtracting}
##' \item{h}{Complex Result}
##' @author Caleb
##' @export
##' @examples
##' all(3,2)
all <- function(x, y){
  f0 <- f(x,y)
  g0 <- g(x,y)
  h0 <- h(x,y)
  list(f=f0, g=g0, h=h0)
}

5. devtools::document() generate R documentation

devtools::document() ## default argument is pkg = ".", current working directory

Change:

• NAMESPACE is updated
• man folder is created

6. usethis::use_data() prepare external data

xxxx <- sample(1000)
usethis::use_data(xxxx)

Change:

• data folder
• after install the package, do the following:

data(xxxx)

6. documenting external data

• no need to export external data

xxxx.R

#' Prices of 50,000 round cut diamonds.
#'
#' A dataset containing the prices and other attributes of almost 54,000
#' diamonds.
#'
#' @format A data frame with 53940 rows and 10 variables:
#' \describe{
#'   \item{price}{price, in US dollars}
#'   \item{carat}{weight of the diamond, in carats}
#'   ...
#' }
#' @source \url{http://www.diamondse.info/}
"xxxx"

6. internal data

• Internal data: These objects are only available within the package namespace.
• Will be saved as sysdata.rda in R/
• No documentation
• Good to put the raw code in data-raw/ for reproducibility purpose

yyyy <- sample(1000)
usethis::use_data(yyyy, internal = TRUE)

• printY.R

##' @export
printY <- function(){
  print(yyyy)
}

7. usethis::use_testthat() prepare test functions

• create test functions

usethis::use_testthat() ## default argument is pkg = ".", current working directory

• actual test function (e.g. testthat/testf.R)

test_that("test if f function is correct", {
    expect_equal(f(1,1), 2)
  }
)

test_that("test if f function is correct", {
    expect_equal(f(1,4), 2)
  }
)

8. devtools::test() preform test

• perform test

devtools::test() ## default argument is pkg = ".", current working directory

9. usethis::use_vignette() generate vignettes

• browse all Vignettes

browseVignettes()

• create our own Vignettes

setwd(WD2)
usethis::use_vignette("Gators")

• Turn build_vignettes on when install the package

devtools::install(build_vignettes = TRUE) 

10. devtools::check() check the package

• check the package

setwd(WD2)
devtools::check() ## default argument is pkg = ".", current working directory

11. devtools::build() build the package

• build() will generate .tar.gz package

## build the package
devtools::build() ## default argument is pkg = ".", current working directory

• an inst folder will be created, which contains your vignettes.

12. devtools::install() install the package

• install the package

devtools::install() ## default argument is pkg = ".", current working directory
devtools::install(build_vignettes = TRUE) ## also build the vignettes

• remove the package

remove.packages("GatorPKG")

• install the pacakge again

install.packages(file.path("~/Desktop","GatorPKG_0.0.0.9000.tar.gz"),repos=NULL,type="source") ## directly with vignettes

13, Package checks

• R CMD check

system("R CMD check ~/Desktop/GatorPKG_0.0.0.9000.tar.gz")

This is equivalent to running the following in linux.

R CMD check ~/Desktop/GatorPKG_0.0.0.9000.tar.gz

14, others (internal function)

• internal function: you want to use internally but don’t want other people to see it.
• If we do not use ##` @export, the function will become a internal function

15a, others (depend on other packages)

• DESCRIPTION file Depends: R (>= 3.6.0), survival

Package: GatorPKG
Title: What the Package Does (one line, title case)
Version: 0.0.0.9000
Authors@R: person("First", "Last", email = "first.last@example.com", role = c("aut", "cre"))
Description: What the package does (one paragraph).
Depends: R (>= 3.6.0), survival
License: What license is it under?
Encoding: UTF-8
LazyData: true
RoxygenNote: 6.1.1

• change your function f.R to depend on coxph

##' Add up two numbers (Description)
##'
##' We want to add up two numbers, blalala... (Details)
##' @title add two numbers
##' @param x first number
##' @param y second number
##' @return sum of two numbers
##' @author Caleb
##' @export
##' @examples
##' f(1,2)
f <- function(x, y){
  print(head(coxph))    
  x + y 
} 

• all visible functions in the survival package will be exported in your package.

15b, others (depend on other packages)

What if you do not want to load the entire dependent package, but only certain functions

• Use @import in your function
• Don’t need to declare dependency in DESCRIPTION

##' Add up two numbers (Description)
##'
##' We want to add up two numbers, blalala... (Details)
##' @title add two numbers
##' @param x first number
##' @param y second number
##' @return sum of two numbers
##' @author Caleb
##' @import survival
##' @export
##' @examples
##' f(1,2)
f <- function(x, y){
  print(head(coxph))    
  x + y 
} 

• update namespace

devtools::document()

• reinstall the package

Your function depends on the external package, but the external package is not loaded.

16, others (R package and GitHub)

• GitHub is a great open platform to host R packages
  • Apply for a github acccount
  • https://github.com
  • Free GitHub pro account (GitHub Education): requires scanning of the UF ID card.
• Play with the following git tutorials (HW)
  • https://www.codecademy.com/learn/learn-git

References

• http://adv-r.had.co.nz
• https://exygy.com/which-license-should-i-use-mit-vs-apache-vs-gpl/