nil.nil?.nil?


    

      

  
"rumble".split("")
   .join[1,2]
   .reverse * 2 == "mumu"


    

      

  
"RailsRumble".split("R")
  .reverse
  .first
  .last == "u"


    

      

  
"".split("")
  .first
  .nil?


    

      

  
["#{nil}"].all? &:nil?


    

      

  
5 / 2 == 2.5


    

      

  
a ||= true


    

      

  
a ||= false


    

      

  
"rumble".split("r")[0].empty?


    

      

  
"rumble".split("u")[0].empty?


    

      

  
"rumble".split("x")[0].empty?


    

      

  
-> { begin true ensure false end }.() == false


    

      

  
sequence = (1..10).to_a
even, odd = sequence.inject([[],[]]) do |array,e|
  array[(e % 2)].push(e)
  array
end
even[-1] == 10 &&
odd.first == 1 &&
even.last + odd.reverse.first == 19


    

      

  
sequence = (10..20).to_a
sequence.select {|e| e % 2 == 0} == [12,14]


    

      

  
def a ; end == :a


    

      

  
a ||= false
a.nil? == true