rails: How do I convert a symbol to a class

Question

Given a symbol in rails, how do I get a Class? So I could call something like:

give_class(:post).find(:all)

or similar.

Answer 1

First, convert to string.

class_name = symbol.to_s

From there, you will need to format the string into a proper class name using the methods provided by ActiveSupport's Inflections module.

• camelize will turn 'my_module' into 'MyModule'
• classify will turn 'my_models' into 'MyModel'

camelize is more likely the one you want, given your code snippet.

The use the constantize method:

klass = class_name.constantize

Classy!

Answer 2

I was searching stackoverflow for this answer and couldn't find it worded how I was looking for it, so I thought I would Q&A myself:

• http://stackoverflow.com/questions/618607/symbol-to-constant-in-rails

The answer above was correct, but I acutally found the docs that explain a bit better:

• http://api.rubyonrails.org/classes/ActiveSupport/CoreExtensions/String/Inflections.html#M001360

There are basically two methods:

• .to_s.camelize - used when you have the singular form (:post)
• .to_s.classify - used when you have a plural form (:posts)

From that, you call constantize, and Viola! you have your class.