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.

Writing an Inherited Class
CodeExpectedActual
class String
  def scramble
    (split //).sort_by { rand }.join
  end
end
"I once was a normal string.".scramble
"i arg cn lnws.Ioateosma n r" "i arg cn lnws.Ioateosma n r" 
class UnpredictableString < String
  def scramble
    (split //).sort_by { rand }.join
  end
  def inspect
    scramble.inspect
  end
end
str = UnpredictableString.new("It was a dark and stormy night.")
 " hsar gsIo atr tkd naaniwdt.ym" " hsar gsIo atr tkd naaniwdt.ym" 
str
 "ts dtnwIktsr oydnhgi .mara aa" "ts dtnwIktsr oydnhgi .mara aa" 
class Array
  def sum(start_at=0)
    inject(start_at) { |sum, x| sum + x }
  end
end
[79, 14, 2].sum
 95 95 
['so', 'fa'].sum('')
 "sofa" "sofa" 
[79, 'so'].sum
 
TypeError: String can't be coerced into Fixnum
...
 
TypeError: String can't be coerced into Fixnum
	from (irb):19:in `+'
	from (irb):19:in `sum'
	from (irb):24:in `inject'
	from (irb):19:in `sum'
	from (irb):24

class NumericArray < Array
  def sum
    inject(0) { |sum, x| sum + x }
  end
end
 nil