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.

Converting and Coercing Objects to Different Types
CodeExpectedActual
"4".to_i
 4 4 
4.to_s
 "4" "4" 
Time.now.to_f
 1143572140.90932 1143572358.01902 
{ "key1" => "value1", "key2" => "value2" }.to_a
 [["key1", "value1"], ["key2", "value2"]] [["key1", "value1"], ["key2", "value2"]] 
def print_each(array)
  array.each { |x| puts x.inspect }
end
hash = { "pickled peppers" => "peck of",
         "sick sheep"      => "sixth" }
print_each(hash.to_a)
 
["sick sheep", "sixth"]
["pickled peppers", "peck of"]
 
["sick sheep", "sixth"]
["pickled peppers", "peck of"]
 
print_each(hash)
 
["sick sheep", "sixth"]
["pickled peppers", "peck of"]
 
["sick sheep", "sixth"]
["pickled peppers", "peck of"]
 
array = hash.to_a
 [["sick sheep", "sixth"], ["pickled peppers", "peck of"]] [["sick sheep", "sixth"], ["pickled peppers", "peck of"]] 
until array.empty?
  item, quantity = array.pop
  puts "#{quantity} #{item}"
end
 
peck of pickled peppers
sixth sick sheep
 
peck of pickled peppers
sixth sick sheep
 
hash.sort
 [["pickled peppers", "peck of"], ["sick sheep", "sixth"]] [["pickled peppers", "peck of"], ["sick sheep", "sixth"]] 
3/4
 0 0 
3/4.to_f
 0.75 0.75 
require 'rational'
Rational(1, 3).to_f
 0.333333333333333 0.333333333333333 
Rational(11, 5).to_i
 2 2 
2.to_r
 Rational(2, 1) Rational(2, 1) 
require 'bigdecimal'
require 'bigdecimal/util'
one_third = 1/3.0
 0.333333333333333 0.333333333333333 
one_third.to_r                                     
NoMethodError: undefined method `to_r' for 0.333333333333333:Float
...
 
NoMethodError: undefined method `to_r' for 0.333333333333333:Float
	from (irb):27

one_third.to_d.to_r
 Rational(333333333333333, 1000000000000000) Rational(333333333333333, 1000000000000000) 
20.to_d                                            
NoMethodError: undefined method `to_d' for 20:Fixnum
...
 
NoMethodError: undefined method `to_d' for 20:Fixnum
	from (irb):29

20.to_r.to_d
 #<BigDecimal:b7bfd214,'0.2E2',4(48)> #<BigDecimal:b7bfd034,'0.2E2',4(48)> 
require 'complex'
i = Complex(0, 1)
 Complex(0, 1) Complex(0, 1) 
i.coerce(3)
 [Complex(3, 0), Complex(0, 1)] [Complex(3, 0), Complex(0, 1)] 
i.coerce(2.5)
 [Complex(2.5, 0), Complex(0, 1)] [Complex(2.5, 0), Complex(0, 1)] 
[1, 2, 3].to_s
 "123" "123" 
[1, 2, 3].inspect
 "[1, 2, 3]" "[1, 2, 3]"