In article <335e48a90905221136y1ce96833va63b74230e1bc646 / mail.gmail.com> you wrote:
> On Fri, May 22, 2009 at 7:08 PM, Ken Bloom <kbloom / gmail.com> wrote:
>> I'm looking to use an inverted index for Ruby. There used to be Zed
>> Shaw's Ruby/odeum that did this using QDBM's inverted index API. I can
>> find references to this all over the web, unfortuntely but the original
>> site is gone and I can't find any mirrors.
>>
>> Can anybody help me out?
> If not maybe you would care to explain what is an inverted index please ;).


An inverted index is an index from terms to the documents that they
appear in. Typically drawn as:

word1 -> doc1, doc2, doc3, doc4
word2 -> doc1, doc4, doc7, doc12
word3 -> doc5, doc6, doc7, doc12

It could be expressed as a Hash of Arrays, but when you start
operating on even medium-small text collections, it can get
inefficient to load the whole thing into RAM when you don't need
to.

-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/