Packages

A common error

What does this common error message suggest? object _____ does not exist.

Load a package

In the code chunk below, load the {tidyverse} package. Whenever you load a package R will also load all of the packages that the first package depends on. {tidyverse} takes advantage of this to create a shortcut for loading several common packages at once. Whenever you load {tidyverse}, {tidyverse} also loads {ggplot2}, {dplyr}, {tibble}, {tidyr}, {readr}, {purrr}, {forcats}, {stringr}, and {lubridate}.

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Solution

library(tidyverse)

Good job! R will keep the packages loaded until you close your R session. When you re-open R, you’ll need to reload your packages.

Quotes

Did you know library() is a special function in R? You can pass library() a package name in quotes, like library("tidyverse"), or not in quotes, like library(tidyverse)—both will work! That’s often not the case with R functions.

In general, you should always use quotes unless you are writing the name of something that is already loaded into R’s memory, like a function, vector, or data frame.

Install packages

But what if the package that you want to load is not installed on your computer? How would you install the {dplyr} package on your own computer?

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Solution

install.packages("dplyr")

Good job! You only need to install a package once, unless you wish to update your local copying by reinstalling the package. Notice that install.packages() always requires quotes around the package name.

Congratulations!

Congratulations. You now have a formal sense for how the basics of R work. Although you may think of your self as a data scientist, this brief computer science background will help you as you analyze data. Whenever R does something unexpected, you can apply your knowledge of how R works to figure out what went wrong.