From: Chuck Remes <cremes.devlist@...>
Date: 2009-07-20T11:13:47+09:00
Subject: Re: removing array duplicates where a subset is unique


On Jul 19, 2009, at 5:07 PM, Siep Korteling wrote:

> David A. Black wrote:
>> Hi --
>>
>> On Mon, 20 Jul 2009, 7stud -- wrote:
>>
>>>>
>>> [2, 2, 3, 40]
>>>   h[key] = suba
>>> end
>>>
>>> end
>>>
>>> p h.values
>>>
>>> --output:--
>>> [[2, 2, 3, 40], [1, 2, 3, 10]]
>>
>> I'm not sure what that buys you, though. The ||= idiom should work
>> fine, unless you need to do something extra during the if statement.
>>
>>
>> David
>
> Facets has enumerable#uniq_by implemented like this:
>
> def uniq_by #:yield:
>    h = {}; inject([]) {|a,x| h[yield(x)] ||= a << x}
> end

Ooh, I like this one too. I'll try it out and see what kind of  
performance I get. I understand that #inject performance is weak in  
MRI 1.8, but I primarily use JRuby where it doesn't share the same  
performance issues as the C version.

cr