From: Robert Klemme <shortcutter@...>
Date: 2008-08-08T16:45:03+09:00
Subject: Re: Most compact command for associate array 'totalling'?

2008/8/8 Chuck Remes <cremes.devlist@mac.com>:
>
> On Aug 7, 2008, at 5:27 PM, Siep Korteling wrote:
>
>> Chuck Remes wrote:
>>>
>>> On Aug 7, 2008, at 4:59 PM, John Pritchard-williams wrote:

>>> a = Hash.new { |h,k| h[k] = 0 }
>>> a["abc"] += 1

>> a = Hash.new(0)
>> a["abc"] += 1
>>
>> Has the same effect.
>
> Quite true, but I find the block form to be a better "general case" form to
> know since it is so much more flexible. But that's just my preference.

That's true in a way - although for this particular case I'd prefer
the solution with the default parameter.  This can be slightly more
efficient at times because it does not insert a value on each query to
the Hash.

For other frequent cases, I use the block form.  This is a typical
(for me) application:

items = Hash.new {|h,k| h[k] = []}
...
items[item.category] << item

Kind regards

robert


-- 
use.inject do |as, often| as.you_can - without end