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Re: Searching for empty string

From: Peter Karman <peter(at)>
Date: Fri Jun 03 2005 - 13:39:19 GMT
There's really not a clean (straightforward) way to do this.

You can probably find some creative ways around it, though. Some might include:

1. if you're using -S prog, use some standard string to indicate no value for a 
property: NA or NONE or something like that. Some string that won't be likely to 
appear in valid properties.

2. search for (not a*) and (not b*) ... and (not z*)
for each of your word characters (start word characters, really). You could set 
that up as a pre-defined query. I would expect it to be really slow 
(comparatively) though, because of all the wildcards.

3. Like #1, but use a low ascii char (a control character) to indicate the 
'empty' property. Then set PropertyNamesNoStripChars config param to 'yes'.

CheHax scribbled on 6/3/05 5:16 AM:

> Hello list,
> I am still working on my search engine (it is working pretty smoothly
> now and should be open in beta) and I was wondering if there is a way
> to search for an empty metatag.
> Say I have 2 metas : company name and company activity.
> I want to search companies with undefined activity, and so an empty string...
> Is there a way to do so ?
> Thanks
> CheHax

Peter Karman  .  .  peter(at)
Received on Fri Jun 3 06:39:20 2005