From: Tom Robinson <tom@...>
Date: 2002-03-29T20:52:36+09:00
Subject: Array#join accept a codeblock?

Is there some way to do something like Array#join that takes a
codeblock to tell it what to join up the array with?  Something
like...

ary = [1,2,3,4,5]
str = ary.myjoin { |idx|
  if idx == 1
    ' ** '
  else
    ' -- '
  end
}

gives str as "1 -- 2 ** 3 -- 4 -- 5"

I have written something like this below, but I was wondering if
there's anything like this in ruby, or if not maybe it could be added
to the next version. :)

class Array
  def myjoin
    outstr = ""
    self.each_index { |idx|
      if idx == self.length - 1
        outstr += self[idx].to_s
      else
        outstr += self[idx].to_s + yield(idx).to_s
      end
    }
    return outstr
  end
end

I'm new to ruby so critiques on this code would be useful.

<aside>
Also wrote using an "inject", but didn't put the index passing in:

class Array
  def inject(n)
    each { |val|
      n = yield(n, val)
    }
    return n
  end
  def myjoin2
    return inject("") { |n, val|
      if n == ""
        n + val.to_s
      else
        n + yield.to_s + val.to_s
      end
    }
  end
end

x = 5
str = ary.myjoin2 {
  x += 1
  x
}

puts str.inspect

-- 
tom@alkali.spamfree.org
remove 'spamfree.' to respond