undefined method `id' in simple Ruby Program

Question

I've found one question like this on stackoverflow, but it doesn't answer my question.

I'm following along with http://www.ruby-doc.org/docs/ProgrammingRuby/ to learn Ruby, but I'm running into problems with the example code and it's frustrating.

person = "Tim"
puts person.id
puts person.type
puts person

The error message I'm getting is:

C:/Users/g3k/Desktop/Ruby/person.rb:2:in `<main>': undefined method `id' for "Tim":String (NoMethodError)

Obviously I'm running Windows (Vista) and I'm running ruby 1.9.2p0 (2010-08-18) [i386-mingw32]. I'm wondering my problem is because the book is outdated and Ruby has had some time to mature since this book came out (the second edition is available for purchase at this point)

I had the same problem with .id in a Jukebox example code, but I figured it was a fluke and continued. I understand what the error is, but I don't understand why.

Answer 1

id is deprecated and replaced with object_id. type is also deprecated. Use class instead.

person = "Tim";
puts person.object_id;
puts person.class;
puts person;

Output: 69284020 String Tim

Refer to http://ruby-doc.org/core/classes/Object.html for Object's methods

Answer 2

Figured it out, I was right, .id is depreciated, .object_id is what should be used.