"rumble".split("")
.join[1,2]
.reverse * 2 == "mumu"
"RailsRumble".split("R")
.reverse
.first
.last == "u"
"".split("")
.first
.nil?
"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]
a ||= false
a.nil? == true