From: Kev Jackson <kevin.jackson@...>
Date: 2005-10-04T12:56:18+09:00
Subject: Odd hash behaviour

Hi all,

I'm still munging data and I'm struggling with Ruby's hash

For example, I want to store a value with an associated key (sounds like 
a hash or associated array), but I don't want duplicates (more like a 
set, in Java I'd use a HashSet to get this behaviour).

@min_pks = Hash.new()
....
# store value for key unless we already have it
@min_pks[min_key] = no unless @min_pks.has_key?(min_key)

Regardless of how I structure the above, the Hash always stores every 
value, it's as if the Hash always returns a false to the query has_key?, 
so it always stores a new value

The key I'm using is a 3 letter abbreviation like 'MID', 'MCY' etc, and 
in the incoming data they are duplicated

I've tried googling, I've tried ri etc, and there doesn't seem to be a 
Set class with Ruby (I'd rather not write my own), at least according to 
the docs.  I'm also aware that the problem is between the keyboard and 
the chair, it's not Ruby's falut, I'm doing something dim.

Anyone help me out?

Kev