Lab 1 - Setting Up R

The R Markdown file for this lab can be found here

The YAML Header

YAML means “Yet Another Markup Language”. You can use this section to customize or add metadata, such as: - date - abstract

You can also add formatting under output: mainfont: Set the main font. ontsize: 11pt: Adjust the base font size. header-includes: Include custom LaTeX packages or commands (e.g. for advanced header/footer customization).

The setup chunk

You should reserve this for global chunk options, loading libraries/packages, and if needed clearing the environment.

Chunk options can be global (applies for your entire document) or local (applies only to a specific chunk). To set global options you can modify the opts_chunk$set() parameters. - echo = TRUE shows your code chunks in the final document. - cache = TRUE tells your machine to save code output as you work, which can be useful if you are slowly working through a large markdown file with lots of code.

You can load libraries in the setup or elsewhere, but it’s generally best to load everything at the top. - Install packages with install.packages("packagename"). These usually only need to be installed once until R gets an update and you have to reinstall all of them again. - Load libraries with library(libraryname). You must install the package containing the library before you can do this.

It is vital that you set your directory correctly. All data should be saved to this directory or the same directory as your script or markdown file. To do so, you can use setwd([directorylocation])in this chunk.

Code Chunks

You can embed code like below. You can customize a few options in the header:

• include = FALSE hides code and results from the finished file.
• echo = FALSE hides code but not results.
• message = FALSE hides messages generated by code.
• warning = FALSE hides warnings.

Defaults for the above are all TRUE.

To make an annotation, put a hashtag at the start. You can also select a section of code and use Ctrl-Shift-C on Windows to make it into an annotation. Annotations will not be treated as code and will not be run.

Activity: Make a cat by customizing chunk options.

cat("  /\\_/\\  (\n ( ^.^ ) _)")
message("   \\\"/  (\n ( | | )")
warning("   /  (\n | )")
cat("(__d b__)")

Other formatting

Header level is indicated by the number of hashtags.

fig.[someoption] allows you to format figures, and results = '[someoption]' allows you to format results. Obviously replace “someoption” with the relevant option.

To add math notation, embed Latex math with “$...$”. Some math environments, like align do not need the dollar signs and work on their own.

You can change font options for some specific words to monospace, bold, or italic.

Trying it out

Let’s make sure that we have everything set up correctly. Please download the file here and put it in the correct directory.

Now let’s make a plot. To do so, we need to learn two things.

• variablename <- value will assign value to variablename
• read.csv(filename.csv) will return the contents of filename.csv as a dataframe.
• plot(x,y) will create a scatterplot.

Don’t worry about what a dataframe is yet.

# df <- read.csv("uscrowdsynth.csv")
# plot(df$income, df$monthtotal)