From: Logan Capaldo <logancapaldo@...>
Date: 2004-12-14T05:19:57+09:00
Subject: Re: [Nuby] Sorting a Hash and keepint it as a Hash?

On Tue, 14 Dec 2004 05:07:03 +0900, Williams, Chris
<Chris.Williams@xeroxlabs.com> wrote:
> Another nuby question:
> 
> I have a Hash of objects which I want to sort by the values. Afterwards
> I want to pull out the keys as one array and the values as another. So I
> have code like so:
> 
> # sort by frequency ascending
> @fault_sums = @fault_sums.sort {|a,b| a[1] <=> b[1]}
> # Only keep top N
> @fault_sums.slice!(0...-@number) if @number <= @fault_sums.size
> 
> fields = @fault_sums.keys
> data = @fault_sums.values
> 
> But when I get to calling keys and values on the Hash I realized, sort
> actually returns back a 2D array and those methods aren't defined on an
> Array. Is there a way to make the 2D Array returned by the sort back
> into a Hash?
> 
> Thanks,
> Chris Williams
> 
> 
Well you could but you'd be back at square one since a hash is
unordered. An alternate method is to sort the keys by the values, ie

keys_ordered = some_hash.keys.sort { |a, b| some_hash[a] <=> some_hash[b] }

keys_ordered.each { |k|
       # do something with some_hash[k]
}

Of course you'll have to change it to fit exactly what you need.