From: brabuhr@...
Date: 2008-11-28T00:54:39+09:00
Subject: Re: Performance issues with large files -- ruby vs. python :

On Thu, Nov 27, 2008 at 10:27 AM,  <brabuhr@gmail.com> wrote:
> On Thu, Nov 27, 2008 at 9:39 AM, sa 125 <s_ayalon@hotmail.com> wrote:
>> if not @main_hash.keys.member?(date)
>>  @main_hash[date] = {}
>
> main_hash[date] ||= {}

Simple benchmark:
http://gist.github.com/29792