[1,2,5,8,3].collect{|i| i.to_s} #=> ["1", "2", "5", "8", "3"]
[1,2,5,8,3].select{|i| i.to_s} #=> [1, 2, 5, 8, 3]
作爲每紅寶石-doc的select => "Returns a new array containing all elements of ary for which the given block returns a true value."
是不是真值在這裏應該i.to_s
值