How do I get the name of a Ruby class?

问题

How can I get the class name from an ActiveRecord object?

I have:

result = User.find(1)

I tried:

result.class
# => User(id: integer, name: string ...)
result.to_s
# => #<User:0x3d07cdc>"

I need only the class name, in a string (User in this case). Is there a method for that?

I know this is pretty basic, but I searched both Rails' and Ruby's docs, and I couldn't find it.

回答1:

You want to call .name on the object's class:

result.class.name

回答2:

Here's the correct answer, extracted from comments by Daniel Rikowski and pseidemann. I'm tired of having to weed through comments to find the right answer...

If you use Rails (ActiveSupport):

result.class.name.demodulize

If you use POR (plain-ol-Ruby):

result.class.name.split('::').last

回答3:

Both result.class.to_s and result.class.name work.

回答4:

If you want to get a class name from inside a class method, class.name or self.class.name won't work. These will just output Class, since the class of a class is Class. Instead, you can just use name:

module Foo
  class Bar
    def self.say_name
      puts "I'm a #{name}!"
    end
  end
end

Foo::Bar.say_name

output:

I'm a Foo::Bar!

回答5:

In my case when I use something like result.class.name I got something like Module1::class_name. But if we only want class_name, use

result.class.table_name.singularize

来源：https://stackoverflow.com/questions/826210/how-do-i-get-the-name-of-a-ruby-class

标签

ruby-on-rails

ruby

rails-activerecord