Ruby Logic

This code snippet creates the output followed below...

#! /usr/bin/env ruby

# Clemens Lee, 2013-10-15

puts
puts "In Ruby, what is true, and what is not."

candidates = [ true, false, Object.new, nil, 1, 0, 1.0, 0.0, "string", "" ]

puts
candidates.each do |x|
  puts "#{x.inspect} is #{x == true}"
  puts "#{x.inspect} is #{!(x == false)}"
end

puts
candidates.each do |x|
  true_or_false = false
  if x
    true_or_false = true
  end
  puts "if #{x.inspect} is #{true_or_false}"
end

...

In Ruby, what is true, and what is not.

true is true
true is true
false is false
false is false
#<Object:0x0000010108ab90> is false
#<Object:0x0000010108ab90> is true
nil is false
nil is true
1 is false
1 is true
0 is false
0 is true
1.0 is false
1.0 is true
0.0 is false
0.0 is true
"string" is false
"string" is true
"" is false
"" is true

if true is true
if false is false
if #<Object:0x0000010108ab90> is true
if nil is false
if 1 is true
if 0 is true
if 1.0 is true
if 0.0 is true
if "string" is true
if "" is true