From: "David A. Black" <dblack@...>
Date: 2004-12-09T00:59:36+09:00
Subject: Re: Idiom for creating hash from two arrays

Hi --

On Thu, 9 Dec 2004, Glenn Parker wrote:

> David A. Black wrote:
>> But what about a hash from two arrays with a default value?
>
> At some point, it becomes more legible to use separate operations:
>
> h = Hash.new(keys, values)
> h.default = "defaultValue"
>
> Hash#default and Hash#default= are already defined.

I know.  I'm still not in favor of changing the signature of Hash#new
to accomodate this particular case.

> Oddly, there is no Hash#default_proc= to complement Hash#default_proc.
>
>> I'm actually more drawn to some kind of #to_h-ish operation on arrays,
>> like:
>> 
>>   key_array.hash_with(value_array)
>> 
>> rather similar to Array#zip, but producing a hash.
>
> This style of expression can only create a new hash instead of updating an 
> existing hash.  I think the "core" operation is updating/merging an existing 
> hash with a set of matched keys and values.

hash.update(key_array.hash_with(value_array)) :-)


David

-- 
David A. Black
dblack@wobblini.net