From: Dave Burt <dave@...>
Date: 2005-10-12T13:56:55+09:00
Subject: Re: small array/hash question


Kev Jackson:
>>> loop across data here
>>> work_types[nsc_id]=do |types|
>>>      types << data[7]
>>> end
>>> end loop
>>> where work_types is the hash and types is the array I want to accumulate 
>>> data in
> ...
> I got the output I wanted with this
>
> work_types = Hash.new
> if work_types.has_key?(nsc_id) then
>    work_types[nsc_id]= work_types[nsc_id].include?(work_type) ? 
> work_types[nsc_id] : work_types[nsc_id] << work_type
> else
>    work_types[nsc_id]= [work_type]
> end
>
> So the problem is solved, but I wonder if there's a more elegant way of 
> doing it (especially the check to see if the value is already in the 
> array).  My first assumption was that assignment to a Hash took a block 
> (hence the pseudo code), I was actually a little suprised that it didn't 
> ;)

How about this?

work_types = Hash.new {|h, k| h[k] = [] }
work_types[nsc_id] << work_type unless 
work_types[nsc_id].include?(work_type)

Cheers,
Dave