This lesson is being piloted (Beta version)

R for Research: Instructor Notes

Dataset

The data used for this lesson are in the figshare repository at: https://figshare.com/articles/SAFI_Survey_Results/6262019.

This lesson uses SAFI_clean.csv. The direct download link for this file is: https://ndownloader.figshare.com/files/11492171.

When time comes in the lesson to use this file, we recommend that the instructors, place the download.file() command in the Etherpad, and that the learners copy and paste it in their scripts to download the file directly from figshare in their working directory. . If the learners haven’t created the data/ directory and/or are not in the correct working directory, the download.file command will produce an error. Therefore, it is important to use the stickies at this point.

RStudio and Multiple R Installs

Some learners may have previous R installations. On Mac, if a new install is performed, the learner’s system will create a symbolic link, pointing to the new install as ‘Current.’ Sometimes this process does not occur, and, even though a new R is installed and can be accessed via the R console, RStudio does not find it. The net result of this is that the learner’s RStudio will be running an older R install. This will cause package installations to fail. This can be fixed at the terminal. First, check for the appropriate R installation in the library;

ls -l /Library/Frameworks/R.framework/Versions/

We are currently using R 3.x.y If it isn’t there, they will need to install it. If it is present, you will need to set the symbolic link to Current to point to the 3.x.y directory:

ln -s /Library/Frameworks/R.framework/Versions/3.x.y /Library/Frameworks/R.framework/Version/Current

Then restart RStudio.

Narrative

Before we start

Intro to R

Starting with data

The two main goals for this lessons are:

Manipulating data with dplyr

Visualizing data with ggplot2

Using databases from R

Technical Tips and Tricks

Show how to use the ‘zoom’ button to blow up graphs without constantly resizing windows

Sometimes a package will not install, try a different CRAN mirror

Alternatively you can go to CRAN and download the package and install from ZIP file

It is important that R, and the R packages be installed locally, not on a network drive. If a learner is using a machine with multiple users where their account is not based locally this can create a variety of issues (This often happens on university computers). Hopefully the learner will realize these issues before hand, but depending on the machine and how the IT folks that service the computer have things set up, it may be very difficult to impossible to make R work without their help.

If learners are having issues with one package, they may have issues with another. It’s often easier to make sure they have all the needed packages installed at one time, rather then deal with these issues over and over. Here is a list of all necessary packages for these lessons.

Other Resources

If you encounter a problem during a workshop, feel free to contact the maintainers by email or open an issue.

For a more in-depth coverage of topics of the workshops, you may want to read “R for Data Science” by Hadley Wickham and Garrett Grolemund.