[ruby-talk:4812] Re: Piping in Ruby?

[e-mail] writes:

>     p list.collect { |i| i.sub(/.*/, "1_#{$&}_1") }

You can't use the $& form in a string parameter to sub, because the
parameters are evaluated _before_ the body of the method is
executed. You have to use \& instead


      def x(list)
          p list

          p list.collect { |i| i.sub(/(.*)/, '1_\&_1') }

          p list.collect { |i| i.sub(/.*/, '1_\&_1') } .
                 collect { |i| i.sub(/.*/, '2_\&_2') }

          print "\n"
      end

      x( %w(a) )
      x( %w(a b c d) )

=>
     ["a"]
     ["1_a_1"]
     ["2_1_a_1_2"]

     ["a", "b", "c", "d"]
     ["1_a_1", "1_b_1", "1_c_1", "1_d_1"]
     ["2_1_a_1_2", "2_1_b_1_2", "2_1_c_1_2", "2_1_d_1_2"]


Regards


Dave