From: soprano <spicyjalapeno@...>
Date: 2008-01-07T03:44:00+09:00
Subject: Re: add rankings to array?

Great, thanks!

On Jan 6, 11:15 am, Robert Klemme <shortcut...@googlemail.com> wrote:
> Preparation:
>
> data = [
>    { :name => "A", :points => 30 },
>    { :name => "B", :points => 20 },
>    { :name => "C", :points => 10 },
>    { :name => "D", :points => 20 }
> ]
>
> Here's one way:
>
> sorted = data.sort_by {|x| -x[:points]}
> ranked = sorted.inject([0,1,nil,[]]) do |(rk, cn, lst, arr), x|
>    tmp_lst = x[:points]
>
>    if tmp_lst == lst
>      cn += 1
>    else
>      rk += cn
>      cn  = 1
>    end
>
>    [rk, cn, tmp_lst, arr << [rk, x]]
> end.last
>
> And here's another:
>
> hashed = data.inject(Hash.new {|h,k| h[k] = []}) do |ha, x|
>    ha[x[:points]] << x
>    ha
> end
> sorted = hashed.sort_by {|k,v| -k}
> ranked = sorted.inject([]) do |arr, (k,v)|
>    rk = arr.size + 1
>    v.each {|x, idx| arr << [rk, x]}
>    arr
> end
>
> Have fun!