1. Installing Packages Introduction to R, Part II
Anna Blackstock
Statistician, Biostatistics and Information Management Office (BIMO)
NCEZID/DFWED

2. Overview In Part I, you learned a lot about the basics, including:
Atomic and composite data types
Atomic: character, numeric, logical
Composite: vector, matrix, data frame, …
Functions
is.* and as.* functions, summary(), names(), subset(), …
Operators (assignment, arithmetic, logical):
=, <-, +, -, *, /, <, >, <=, >=, !=, ==

3. Overview
Part II will be about extending R so that you can use it in your work
We’ll cover:
Installing R packages
Getting data in and out of R
Exploring data
Writing functions

4. R Packages Packages are constantly being developed
There are almost 13,000 add-on packages available*
Packages are constantly being developed
After development, packages are available immediately
Go to for links to lists of packages.
*This number has more than doubled from 5000 in 2013.

5. What is an R package?
R packages are collections of functions, datasets, and code that are available for download
Functions in a package often have a common theme
Importing data (haven, readxl, rgdal, …)
Statistical analysis (survey, survival, ...)
Producing graphs (lattice, ggplot2, ...)
For more information, see

6. Which packages do you want?
Usually, the need comes before the downloading of a package!
Think about:
the data you have at hand
the analysis you would like to do or the plot you would like to create
Note: the quality of packages and package documentation can vary.

7. Which packages do you want?
For (trusted) packages by area, see project.org/web/views/

8. How do you get packages into R?
To use functions in a package, you need to do two things:
Install the package (once)
Load the package (before every use)
(For installation in RStudio, you can also go to Tools -> Install Packages…)

9. Installing R Packages . . . at the CDC
CDC users generally cannot make changes to folders where programs are saved (C:/Program Files)
The default location for installing R packages is in this folder, so you’ll need to:
create a new folder elsewhere
tell R to install packages in and load packages from this new folder
(or save R somewhere else, but we won’t cover this)

10. Installing R Packages . . . at the CDC
The RUG website has detailed instructions on installing packages at the CDC.
Method 2 has two options:
“every time way”: specify package location each time packages are saved or used
“forever way”: specify package location in file where R sees start-up commands
See

11. The CRAN Mirror
When you install packages, you are downloading from a CRAN (Comprehensive R Archive Network) mirror, a replica of all R code and documentation
SciComp and RUG have set up a local CRAN mirror: