From: "Kroeger Simon (ext)" <simon.kroeger.ext@...>
Date: 2005-09-06T17:29:12+09:00
Subject: Re: [Q] how to do insertion and smooth traversal simultaneously on array

 

> -----Original Message-----
> From: Robert Klemme [mailto:bob.news@gmx.net] 
> Sent: Tuesday, September 06, 2005 10:26 AM
> To: ruby-talk ML
> Subject: Re: [Q] how to do insertion and smooth traversal 
> simultaneously on array
> 
> Kroeger Simon (ext) wrote:
> > as Robert said:
> > -----------------------------------------------------------------
> > a = [ 0, 1, 2, 3, 4, 5 ]
> > actions = []
> > a.each_with_index do |x, i|
> >   puts "[#{i}] : #{x}"
> >   if i % 2 == 0  # even index ?
> >     actions << [a, :insert, [i, ':-)']]
> >   end
> > end
> > # do it!
> > actions.reverse.each{|action| action[0].send(action[1], *action[2])}
> > puts a.size
> > ------------------------------------------------------------------
> 
> You can slightly simplify this as
> 
> a = [ 0, 1, 2, 3, 4, 5 ]
> actions = []
> a.each_with_index do |x, i|
>   puts "[#{i}] : #{x}"
>   if i % 2 == 0  # even index ?
>     actions << [a, [:insert, i, ':-)']]
>   end
> end
> # do it!
> actions.reverse.each{|obj, args| obj.send(*args)}
> puts a.size, "", a
> 
> Although I like the idea to use #send in this case a simpler solution
> would be sufficient:
> 
> a = [ 0, 1, 2, 3, 4, 5 ]
> actions = []
> a.each_with_index do |x, i|
>   puts "[#{i}] : #{x}"
>   if i % 2 == 0  # even index ?
>     actions << [i, ':-)']
>   end
> end
> # do it!
> actions.reverse.each{|idx, val| a.insert(idx, val)}
> puts a.size, "", a
> 
> Kind regards
> 
>     robert

:) in _this_ case somrthing like this would sufficient:

a = [ 0, 1, 2, 3, 4, 5 ]
(a.size / 2).times {|i| a.insert(i*3, ':-)')}

cheers

Simon