How do I create a class instance from a string name in ruby?

In rails you can just do:

clazz = 'ExampleClass'.constantize

In pure ruby:

clazz = Object.const_get('ExampleClass')

with modules:

module Foo
  class Bar
  end
end

you would use

> clazz = 'Foo::Bar'.split('::').inject(Object) {|o,c| o.const_get c}
  => Foo::Bar 
> clazz.new
  => #<Foo::Bar:0x0000010110a4f8>

Very simple in Rails: use String#constantize

class_name = "MyClass"
instance = class_name.constantize.new

Try this:

Kernel.const_get("MyClass").new

Then to loop through an object's instance variables:

obj.instance_variables.each do |v|
  # do something
end

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