puts [1,2,3,4].collect { |i| i.to_s + "x" }puts [1,2,3,4].detect { |i| i.between?(2,3) }puts [1,2,3,4].select { |i| i.between?(2,3) }puts [4,1,3,2].sortputs [1,2,3,4].maxputs [1,2,3,4].min