From: Idan Sofer <idan@...>
Date: 2003-02-04T22:27:00+09:00
Subject: Re: Mismatch between documenation and implementation of Array#join()

Robert Klemme wrote:

>Hi,
>
>I'm wondering whether Array#join() has an error or the documentation is
>wrong. Documentation says:
>"Returns a string created by converting each element of the array to a
>string, separated by aSepString." This apparently does not include
>flatten(). But the behavior seems to be like flatten() was invoked before:
>
>With Ruby version 1.6.7:
>
>irb(main):015:0* a=[[0,1],[22,33]]
>[[0, 1], [22, 33]]
>irb(main):016:0> a.join(";")
>"0;1;22;33"
>  
>
>I would have expected a.join(";") to have returned "01;2233" instead.
>
I seem to think it is the correct behaviour, Array#join is just invoked 
in each of the subarrays as well(Recursive behaviour, just as #to_s 
calls #to_s on all of the array members), however, your wish might be 
fulfilled this way:

a.map { |x| x.to_s }.join(';')

or:

class Array

  def join_s(sep=nil)
    map {|x| x.to_s}.join(sep)
  end
end

a.join_s

Idan.