Other Tools to help you learn Ruby

ri

ri is a tool to look up ruby documentation:

$ ri String.split
= String.split

(from ruby core)
------------------------------------------------------------------------------
  str.split(pattern=$;, [limit])   => anArray

------------------------------------------------------------------------------

Divides str into substrings based on a delimiter, returning an array of
these substrings.
...

You can do a lot with it:

• ri Class -- looks up the class documentation and shows all the methods available.
• ri Class.method -- looks up a specific method on a class or module.
• ri method -- searches all classes for matching methods

If running ri doesn't work and you've installed ruby using rvm, try running this command first:

$ rvm docs generate

irb

We've already introduced irb above, but it can't be stressed enough that having an interactive live session with ruby is invaluable. You can learn a lot from it.

Add this to a file called ~/.irbrc:

class Object
  def pim inherited = false
    self.class.public_instance_methods(inherited).sort -
      Object.public_instance_methods
  end
end

Now you can do stuff like:

$ irb
>> "blah".pim
=> ["%", "*", "+", "<<", "<=>", "[]", "[]=", "bytes", "bytesize", ...]

All of these methods are available for any string. You can then use ri to look up the method documentation. It is a great way to find goodies!

online resources

• Ruby Quickref
• The Google - searching "ruby" and whatever you're looking for usually leads to good stuff.
• Ruby Koans - a great set of lessons in an interactive form.
• Learn to Program by Chris Pine - also available as a book.
• The Pickaxe - The definitive ruby reference (and has a great tutorial too).
• Why's (poignant) Guide to Ruby_Guide_to_Ruby) - the (crazy) guide to ruby... Try it, you might like it.