This page contains automated test results for code from O'Reilly's Ruby Cookbook. If this code looks interesting or useful, you might want to buy the whole book.

Hashes
CodeExpectedActual
empty = Hash.new
 {} {} 
empty = {}
 {} {} 
numbers = { 'two' => 2, 'eight' => 8}
 {"two"=>2, "eight"=>8} {"two"=>2, "eight"=>8} 
numbers["two"]
 2 2 
numbers["ten"] = 10
 10 10 
numbers
 {"two"=>2, "eight"=>8, "ten"=>10} {"two"=>2, "eight"=>8, "ten"=>10} 
numbers.keys
 ["two", "eight", "ten"] ["two", "eight", "ten"] 
numbers.values
 [2, 8, 10] [2, 8, 10] 
numbers.to_a
 [["two", 2], ["eight", 8], ["ten", 10]] [["two", 2], ["eight", 8], ["ten", 10]] 
motto = "Don't tread on me" 
flag = { :motto => motto, 
         :picture => "rattlesnake.png"}
motto.upcase!
flag[:motto]
 "DON'T TREAD ON ME" "DON'T TREAD ON ME" 
a = ["Maury", "Momento", "123 Elm St.", "West Covina", "CA"]
h = { :first_name => "Maury",
      :last_name => "Momento",
      :address => "123 Elm St."
      :city => "West Covina",
      :state => "CA" }
a = [1, 4, 9, 16]
h = { :one_squared => 1, two_squared => 4, three_squared => 9,
      :four_squared => 16 }
class BadIdea
  def hash
    100
  end
end
class StringHolder
  attr_reader :string
  def initialize(s)
    @string = s
  end
  def ==(other)
    @string == other.string
  end
  def hash
    @string.hash
  end
end
a = StringHolder.new("The same string.")
b = StringHolder.new("The same string.")
a == b
 true true 
a.hash
 -1007666862 -1007666862 
b.hash
 -1007666862 -1007666862