Click here to navigate the course.

Drag the edges to resize the window.

In Projects, you can keep track of your progress as you go throught the tasks. Check each item as you complete it!

Code Editor
Learn
Hashes and Symbols

What are Symbols Used For?

Symbols pop up in a lot of places in Ruby, but they're primarily used either as hash keys or for referencing method names. (We'll see how symbols can reference methods in a later lesson.)

sounds = { :cat => "meow", :dog => "woof", :computer => 10010110, }

Symbols make good hash keys for a few reasons:

  1. They're immutable, meaning they can't be changed once they're created;
  2. Only one copy of any symbol exists at a given time, so they save memory;
  3. Symbol-as-keys are faster than strings-as-keys because of the above two reasons.
Report a Bug
If you see a bug or any other issue with this page, please report it here.