[GRASS5] randomly select polygons?

[Jeff D. Hamann]

I'm a little stuck....

I would like to randomly select polygons and I'm not sure how to do it. I've
thought about converting the polygon map into a rast map, then using
mapcalc, but since mapcalc works cell by cell, I won't get the entire
polygon. I'm using GRASS 5.3 since I seem to be having build troubles with
GRASS 5.7 and I don't know how to add multiple attributes to a vector map in
5.3. If I could then,  I could perform some type of (and I'm dreaming here)
"select * into rand.trainploys from trainpolys where rand() > 0.5"

I haven't attempted to build 5.7 in some time and can't spend the day
trying.

Thanks,
Jeff.

---
Jeff D. Hamann
Forest Informatics, Inc.
PO Box 1421
Corvallis, Oregon USA 97339-1421
541-754-1428
jeff.hamann at forestinformatics.com
www.forestinformatics.com