Many other approaches are available for creating plots in R. In fact, the plotting capabilities that come with a basic installation of R are already quite powerful. There are also other packages for creating graphics such as grid and lattice. We chose to use ggplot2 in this book because it breaks plots into components in a way that permits beginners to create relatively complex and aesthetically pleasing plots using syntax that is intuitive and comparatively easy to remember.

One reason ggplot2 is generally more intuitive for beginners is that it uses a grammar of graphics¹, the gg in ggplot2. This is analogous to the way learning grammar can help a beginner construct hundreds of different sentences by learning just a handful of verbs, nouns and adjectives without having to memorize each specific sentence. Similarly, by learning a handful of ggplot2 building blocks and its grammar, you will be able to create hundreds of different plots.

Another reason ggplot2 is easy for beginners is that its default behavior is carefully chosen to satisfy the great majority of cases and is visually pleasing. As a result, it is possible to create informative and elegant graphs with relatively simple and readable code.

One limitation is that ggplot2 is designed to work exclusively with data tables in tidy format (where rows are observations and columns are variables). However, a substantial percentage of datasets that beginners work with are in, or can be converted into, this format. An advantage of this approach is that, assuming that our data is tidy, ggplot2 simplifies plotting code and the learning of grammar for a variety of plots.

To use ggplot2 you will have to learn several functions and arguments. These are hard to memorize, so we highly recommend you download the ggplot2 cheat sheet². The downloaded file has a higher quality than the images below.

(Image courtesy of RStudio³. CC-BY-4.0 license⁴.)

Other useful cheat sheets can also be found at https://www.rstudio.com/resources/cheatsheets/⁵.