From: William James <w_a_x_man@...>
Date: 2007-05-01T05:05:05+09:00
Subject: Re: Array.which_long? ( I coded an extension for Array )

On Apr 30, 6:47 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> On 30.04.2007 12:39, Robert Dober wrote:
>
>
>
> > On 4/30/07, Robert Klemme <shortcut...@googlemail.com> wrote:
> >> On 29.04.2007 16:11, Chris Carter wrote:
> >> > On 4/29/07, Billy Hsu <ruby.maill...@gmail.com> wrote:
> >> >> Hi, I'm CFC
> >> >> I'm new at here.
> >> >> Nice to meet you:)
>
> >> >  > I just coded an extension for Array.
> >> >> It will return the longest element of an array.
> >> >> Source:
>
> >> >> class Array
> >> >>   def which_long?
> >> >>     # Version 1.0
> >> >>     # Coded by CFC < zusocfc @ gmail . com >
> >> >>     # PLEASE DO NOT REMOVE THE COMMENT OF THIS FUNCTION, THANKS A LOT.
> >> >>     # Usage:
> >> >>     #   ['a', 'ab', 'abc' 1234].which_long?
> >> >>     #   => 1234
> >> >>     max, long, self_cpy = 0, "", []
> >> >>     self.size.times{|i| self_cpy << self[i].to_s}
> >> >>     self_cpy.each{|item| (max = item.size; long = item) if item.size >
> >> >> max }
> >> >>     long
> >> >>   end
> >> >> end
>
> >> >> Usage:
> >> >>   puts [1, 23, '456'].which_long?
> >> >>   => 456
>
> >> >> CFC --
>
> >> > How about:
> >> > class Array
> >> >  def longest
> >> >    self.map {|x| x.to_s }.sort_by {|x| x.size}[-1]
> >> >  end
> >> > end
>
> >> Thank you for leaving the #inject solutions to me. :-)
> > Are you kidding I posted an inject solution 19h ago ;)
>
> I am sorry, I did not see it.
>
> > But it was to return an array of all longest elements, I guess you can
> > maybe refine it, it seems clumsy, so I repost it just if you have some
> > time to play ;)
>
> > def longest
> >          inject([]){ |s, e|
> >                 if s.empty? || s.first.size < e.to_s.size then [e]
> >                 elsif s.first.size == e.to_s.size then s << e
> >                 else s
> >                 end
> >               }
> > end
>
> Hm, I'd probably use case here.  Let's see...
>
> def longest
>    inject([]) do |lg, e|
>      case
>        when lg.empty?, lg.first.size == e.size
>          lg << e
>        when lg.first.size < e.size
>          [e]
>        else
>          lg
>      end
>    end
> end
>
> Alternative, but with higher memory consumption
>
> def longest
>    lg = Hash.new {|h,k| h[k] = []}
>    each {|x| lg[x.size] << x}
>    lg.sort_by {|k,v| k}.last.pop
> end

def longest
    max = map{|s| s.size}.max
    select{|s| s.size == max}
end