From: Anurag Priyam <anurag08priyam@...>
Date: 2011-07-01T20:15:29+09:00
Subject: Re: How to order Structs based on two fields

On Fri, Jul 1, 2011 at 4:22 PM, Ińaki Baz Castillo <ibc@aliax.net> wrote:
> Hi, I've a struct like this:
>
>  KK = Struct.new(:a,:b)
>
> and some entries in an array:
>
>  kk1=KK.new(0,10)
>  #<struct KK a=0, b=10>
>
>  kk2=KK.new(0,5)
>  <struct KK a=0, b=5>
>
>  kk3=KK.new(2,0)
>  #<struct KK a=2, b=0>
>
>  kk4 = KK.new(2,5)
>  #<struct KK a=2, b=5>
>
>  array = [kk3, kk2, kk1, kk4]
>
>
> I need to order the array based:
> - Elements with minor :a must be first.
> - If two elements have same :a, then order based on higher :b.
>
> The result should be:
>
>  [kk1, kk2, kk4, kk3]
>
>
> I expected that the following could work:
>
>  array.sort_by{|entry| entry.a or entry.b}

How about:

array.sort do |i, j|
  r = i.a <=> j.a
  case r
    when 0 r
    else  -1 * (i.b <=> j.b)
  end
end


-- 
Anurag Priyam
http://about.me/yeban/