How to implement Enums in Ruby?

ruby enums
auramo picture auramo · Sep 16, 2008 · Viewed 184.9k times · Source

What's the best way to implement the enum idiom in Ruby? I'm looking for something which I can use (almost) like the Java/C# enums.

Answer

mlibby picture mlibby · Sep 16, 2008

Two ways. Symbols (:foo notation) or constants (FOO notation).

Symbols are appropriate when you want to enhance readability without littering code with literal strings.

postal_code[:minnesota] = "MN"
postal_code[:new_york] = "NY"

Constants are appropriate when you have an underlying value that is important. Just declare a module to hold your constants and then declare the constants within that.

module Foo
  BAR = 1
  BAZ = 2
  BIZ = 4
end

flags = Foo::BAR | Foo::BAZ # flags = 3

Related questions

Saving enum from select in Rails 4.1

I am using the enums in Rails 4.1 to keep track of colors of wine. Wine.rb class Wine < ActiveRecord::Base enum color: [:red, :white, :sparkling] end In my view, I generate a select so the user can select a …

Read More
How do I describe an enumeration column in a Rails 3 migration?

How do I describe an enumeration column in a Rails 3 migration?

Read More
How to check if a value exists in an array in Ruby

I have a value 'Dog' and an array ['Cat', 'Dog', 'Bird']. How do I check if it exists in the array without looping through it? Is there a simple way of checking if the value exists, nothing more?

Read More