2 Documentation

R comes with rich built-in documentation that you can access by typing ? before the name of a function. The documentation isn’t always aimed at newcomers, and may use terminology that you’re not familiar with. But don’t despair! Ignore what you don’t understand, and persevere. Often you’ll find what you need in the examples at the bottom of the help page.

There are three commands in R that you should be familiar with:

• ?function_name opens the help for function_name(). If you know the name of the function, this will tell you how it works and how you can control its operation. (? also works for built-in datasets).

  If you ever wonder which package a function comes from, you can use ? to figure it out - just look at the top-left of the help page; the package name is surrounded in {}.

• help(package = "package_name") lists all the functions available in a package with links to their help pages.

• browseVignettes(package = "package_name") lists all the “vignettes” available for a package. Vignettes are longer documents that describe how multiple functions work. Many packages include an introductory vignette that give you the lay of the land: these are useful to read before you know the name of the function you need.