Section with Kiyoshi (Slides adapted from Harrison Ting’s) Ruby!

Readings The Ruby Programming Language Read Chapter 1 Skim Chapters 2-7 Read sections 8.9 and 8.10

Running ruby ruby: execute from command line – ruby myProgram.rb irb : interactive command line interpreter – Write program in the command line or… – Import ruby file: source ‘myProgram.rb’ – Run ruby file: load ‘myProgram.rb’ SciTE: IDE bundled with ruby install – Sorry Mac and linux users, Windows only – Edit – Execute

Example #1: Classes Files: – greeter.rb – spanishGreeter.rb – copyGreeter.rb – greeterCounter.rb Constructor Instance methods and variables Subclassing – Inheritance – super Class methods and variables

Example #2: Control Files – printTwice.rb Adding a method to a class

Example #3: Control cont. Files – firstElement.rb – firstElementWithYield.rb – firstElementWithYieldAndEnumerable.rb Adding a method to a module Blocks and Iterators yield – Can yield more than one value

Example #4: eval ’s Files – eval.rb – classEval.rb eval vs. class_eval – class_eval executes in the context of the class – eval executes in the current context

Example #5: Regular Expressions Use for pattern matching

Regular Expressions cont. Literals – /1/.match("012") – matches – "012".match(/1/) – does the same thing – /1/.match("789") – doesn’t match

Regular Expressions cont. Character classes – /[db]og/.match("dog") – /[db]og/.match("bog") – /[0-9]/.match("Ruby 123") – /[a-z]/.match("Ruby 123") – /[A-Z]/.match("Ruby 123") – /[a-zA-Z0-9]/.match("Ruby 123") – /[^Rub]/.match("Ruby 123")

Regular Expressions cont. Special character class: “.” – /.og/.match("dog")

Regular Expressions cont. Repetition – “?” matches 0 or 1 /ruby?/.match("rub") /ruby?/.match("rubyyy") – “*” matches 0 or more /ruby*/.match("rub") /ruby*/.match("rubyyy") – “+” matches 1 or more /ruby+/.match("rub") /ruby+/.match("rubyyy")

Regular Expressions cont. Putting it all together – /[aeiou]+/.match("aardvark")

Regular Expressions cont. (, ), [, ], {, },., ?, +, *, |, ^, $, \ have special meaning – Escape each one to use it literally Files – regexp.rb See section 9.2 for more information

Example #6: Sorting Files – absoluteSort.rb

Example #7: method_missing Files – methodMissing.rb

Example #8: Hash Files – hashMe.rb

Questions?