From: martindemello@... (Martin DeMello)
Date: 2002-11-19T20:29:10+09:00
Subject: Re: ruby-dev summary 18711-18810

"Aleksei Guzev" <aleksei.guzev@bigfoot.com> wrote in message news:<arac16$gmero$1@ID-167200.news.dfncis.de>...
> "Minero Aoki" <aamine@loveruby.net> wrote in message
> news:20021118181718N.aamine@mx.edit.ne.jp...
> > Hi all,
> >
> > This is a summary of ruby-dev ML in these days.
> >
> > [ruby-dev:18651] Enumerable#zip (contd.)
> >
> 
> Aplying zip as an instance method to the module Enumerable makes the method
> assymetric. There is the object left to the method name, and its parameters.
> But in mind the operation is symmetrical except the order is significant.
> Where should the object be placed in sequence?

OTOH, the reason I don't like Kernel#zip is that it implies a false
symmetry which breaks in the case len(a) < len(b). What I'd expect in
the two cases would be

a = [1,2,3]
b = [5,6,7,8,9]
a.zip(b) # => [[1,5], [2,6], [3,7]]
zip(a,b) # => [[1,5], [2,6], [3,7], [nil,4], [nil,5]]

I still think a zipf (zip with function) would be useful too

  a.zipf {|i| f} # => [[a1, f(a1)], [a2, f(a2), ...]

Frinstance the Schwartzian transform could then be written

def stsort(&block)
  zipf(&block).sort(a[1] <=> b[1]}.map(|a| a[0]}
end

martin