Environments

Going Further

The information on this page is largely optional. It’s good to have some awareness of R’s global environment and how R stores the objects you create, but you can safely progress to the next module without mastering these concepts.

Advanced Reading

Advanced R: Environments

Every R command is executed in a particular environment. Conceptually, you can think of R environments as collections of the objects that R currently has stored in working memory. For most day-to-day R usage, you only need to consider one of R’s several types of environment: the Global Environment.

The Global Environment

The global environment is the highest-level environment that R maintains. This environment contains all of the objects you define in your R session. Whenever you create a new object (as you’ve been doing throughout this module), that object lives in the global environment.

Note

Since the global environment is the one you’ll interact with most frequently, its often treated as the default environment when economizing language (i.e., being lazy) or picking software defaults.

  • In these tutorials, whenever we refer to “the environment”, “your current environment”, “your R session”, or some variation of those terms, we’re talking about the global environment.
  • The Environment tab in RStudio shows the contents of the global environment, by default.
  • The interactions described below all interface with the global environment, by default.

Interacting with the (Global) Environment

We can use the ls() function to list the contents of the current environment.

ls()
character(0)

In this case, the environment is empty because we haven’t yet defined any objects.

Do: Run the following code to add some objects to the current environment.

Do: Use the interactive editor below to run the ls() function. What do you see?

You should now see a listing of all the objects you just created. Remember: whenever we create a new object, we’re storing that object in the global environment.

The rm() function will remove an object from the environment.

Do: Run the following code.

See: What effect did rm(x) have?

The listing returned by ls() no longer shows x, because you removed x from the environment by calling rm(x).

Practice
  1. Use the ls() function to view the contents of the environment.
  2. Use the rm() function to remove age from the environment.
  3. Use ls() to check your work.
ls()
[1] "age"  "name" "y"    "z"   
rm(age)
ls()
[1] "name" "y"    "z"
Ready to Continue?

You’re ready to progress if you can:

If any of these concepts still feel shaky, that’s completely fine. Revisit the relevant section before proceeding.

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