[AccessD] "fuzzy logic" search

Thanks.

John W. Colby
www.colbyconsulting.com

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of Stuart
McLachlan
Sent: Wednesday, October 22, 2003 6:18 PM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] "fuzzy logic" search


On 22 Oct 2003 at 9:26, John Colby wrote:

> Stuart,
>
> Could you comment the code for me?  I have no idea what the hamming
distance
> is trying to accomplish and don't wish to take a class to figure it out.
> Just a 1 paragraph overview at te top and a couple of line comments thrown
> in would be a great help.
>

Sorry, I thought it was fairly obvious.

Hamming Distance is a measure of the "differentness" of two strings:
It is just a count  of the number of locations within a string  which
are different. The function just checks whether the two strings are
the same length and then steps through them comparing the character
at each location.

I used a flag of -1 to indicate that the strings where a different
length.
A perfect match  has a Hamming Distance of 0.
If one character has been mistyped, there will be a Hamming Distance
of 1.  If two mistypes (including  a transposition of two digits) the
Hamming Distance will be 2 etc.

I just check for a Hamming Distance of 1, or a distance of 2 where
the checksum of the two strings is the same (an indication that they
are likely to contain the same set of characters)


--
Lexacorp Ltd
http://www.lexacorp.com.pg
Information Technology Consultancy, Software Development,System
Support.



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