The aim of Devtools is to make package development easier by providing R functions that simplify common tasks. A package is a template or set of conventions that structure your code. In common words, it's the collection of several functions which makes our task easy. We used roxygen2 for documentation and testthat for testing.

1. DevTools
Package Development
BATCH - D
GROUP - D8
Sagar Deogirkar(10547321)
Ajay (10546004)

2. INDEX
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1. Introduction
2. Installing DevTool in R
3. Creating New Package
4. Package Name Checking
5. Adding New Function in Package
6. Package Files
7. Package Description
8. Function Documentation with Roxygen
9. Adding Namespace File
10. Function Import & Export with Roxygen
11. Vignette
12. Package Testing
13. Data Inclusion in Package

3. INTRODUCTION
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The aim of Devtools is to make package development easier by providing
R functions that simplify common tasks.
A package is a template or set of conventions that structures your code. In
common words its the collection of several functions which makes our
task easy.
We are going to use roxygen2 for documentation and testthat for testing.

4. Installation
Installing DevTools in R

5. Installing DevTools in R
Current Version – 2.2.2
Command :
install.packages(" usethis ")
install.packages("devtools")
library(devtools)
Note: To be able to build package, we need to install latest version of
RTools. Latest Version is “Rtools35”
Link: https://cran.r-project.org/bin/windows/Rtools/ - For Windows
https://cran.r-project.org/bin/macosx/ - For Mac
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6. New Package
Creating New Package in R

7. Creating New Package in R
Steps:
1. Go to File
2. Select New Project
3. Select New Directory
4. Select R Package
5. Enter Package Name
6. Click Create Project.
7. Automated (Hello) function will be
generated in hello.R file.
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8. Creating New Package in R
• Automated files will be generated in the root directory. Including Description
file, man & folder, Namespace file & a Rproj will be created with the provided
name.
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9. Adding New Function in different file
▪ We can make changes in the same function or can create a new
function in same or different file with .R extension.
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10. Creating New Package in R (Alternative Method)
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•Command- devtools::create("path/to/name")

11. Creating New Package in R (Alternative Method)
•Automated Package files will be generated in the root directory. Including
Description file, R folder, Namespace file & an Rproj will be created with the
provided name.
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12. Creating New Package in R
How to check if the package name is available?
Steps:
1. Install package available.
2. Load library(available)
3. Check with-
available(“package name")
4. R will show if the given
package name is available on
different repository or not.
5. Accordingly name can be
changed if desired to upload on
any of the repository.
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13. Package Files

14. 14
Package Files
•Description: This file describes your
work, sets up how your package will
work with other packages, and applies
a copyright.
•MAN: It contains the documentation
for your functions, the help pages in
your package.
•Namespace: This file helps you make
your package self-contained. It won’t
interfere with other packages, and
other packages won’t interfere with it.
•Test: This folder is used to store tests
that will alert you if your code breaks.
•R: All of the R code (functions) in your
package goes in R/. A package with just
an R/ directory is still a very useful
package.
•Vignette: This is basically an online
guide for the package that help the user
of package to solve the problem.
•Data: It’s often useful to include data in
a package. If you’re releasing the
package to a broad audience, it’s a way
to provide compelling use cases for the
package’s functions.

15. Package Description

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Package Description
Description file is used to show the details of a New Package
• Title should always be in title case (First letter of every word is capital)
• Author: Name of the Package Designer.
• Maintainer: Name of the package maintainer.
• Description: Describe functionality of the package.

17. Function
Documentation
Generating Function Documentation
with Roxygen

18. Function Documentation
• Automated documentation
will be created in MAN folder
with function.Rd name.
Eg: hello.Rd
• We can check default
documentation with
command- ?function name
• Eg: ?hello
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19. 19
Generating Function Description with Roxygen
Steps :
To make R allow to generate Documentation with
Roxygen2 -
1. Open Build
2. Choose Configure Build Tools
3. Check Generate Documentation with Roxygen
4. Choose configure and check all fields which
you want to generate with Roxygen2.
5. Write “—as-cran” in Check Package
To generate Documentation file :
1. Open Code
2. Choose Insert Roxygen Skeleton
3. It will generate tags to describe function.
4. Edit the tags and click ‘clean & rebuild’ in
Build.

20. 20
Generating Function Description with Roxygen
Recompiling the package will
generate .Rd (documentation) file
generated using Roxygen inside
‘Man’ folder with function name.
This documentation file is read
only.

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Important Roxygen Tags
•@param – Indicates Parameters used in a function
•@example – Indicates working example of a function.
•@return – Indicates the output of the function
•@export – Indicates where the function is exported.
•@seealso – Indicate the cross-linked documentation file.

22. Namespace File

23. The Namespace File
• The NAMESPACE file allows R packages to
communicate with one another.
• It can export your functions to make them
available to others and import functions
from other packages if you use them in
your code.
• Roxygen2 can be used to export and
import functions.
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24. Function Import &
Export with Roxygen

25. Function Import and Export with Roxygen
• export() = Exports your functions
(@export in roxygen2).
• import() = Imports all functions from
other packages (@import).
• ImportFrom() = Imports specific functions
from a single package (@importFrom)
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26. Vignette File
How to create/build a vignette folder
for our package

27. Vignette file
• Vignettes is basically a online guide
book/notes for your package that help the
user of your package to solve the problem .
• Vignettes are very useful for packages which
are Use to solve complex algorithm
problems.
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28. Create/Build a Vignette Folder for The Package
• Before creating we need to install
Rmarkdown package.
• Command- install.packages("rmarkdown")
• Create Vignette command-
usethis::use_vignette("title of your vignette" )
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29. Package Testing

30. Package Testing
• Command- usethis::use_testthat()
It will create “tests” folder in
package file where, test file will be
stored.
• Create a new file in
package > tests > testthat
to test the function (Here we are
testing printer function as shown
in slide 13).
• Write package test code in
test_that.
• Can use different testthat functions
to tally output.
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31. Package Testing
• Command- devtools::test() Use this command to test the package.
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32. Data File
Including data in Package

33. Data Inclusion in Package
• It’s often useful to include data in a
package if you’re releasing the package to
a broad audience.
• Command- use_data_raw() { creates data
folder in package }
• Define your data and to save your data in
package use command :
• usethis::use_data("DATA name")
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34. Thank You!
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