Hi Dav, El dt 07 de 03 del 2006 a les 16:05 -0800, en/na Dav Clark va escriure: > Hello, > > I just started looking at PyTables for a project, and am looking for some > advice. > > Problem in brief - > > * I have a variety of medical (brain) imaging datasets that I need to store. > This includes things like arbitrary selections of some region of the data > (e.g. a list of 3-number indices into a volume). > > * These indices are inherently variable length - users might specify many or > few indices > > * Other pieces of data that go with would fit easily into fixed-length > records > in a Table > > Possible solutions - > > * I have seen talk (in 2004!) of a VLTable class, which would do exactly what > I'd like. Is this in the works?
Yeah, the VLTable class would be the way to go (it would be handy not only for your project, but for a bunch of others). Unfortunately, the implementation of a truly efficient VLTable class would imply having a combination of EArray and VLArray classes as the building blocks of the new beast. While is is not complicated conceptually, it supposes that we should write a great deal of code, and, at the moment, no one has stepped ahead neither to contribute code nor to sponsorize the job. > * I could have a separate table for fixed-length records and an associated > VLArray, and just make sure I'm careful. Yes, I think this is your best bet right now. Defining an Atom for the 3-number indices and keeping a variable length of these on each VLArray object would be a good approach. Fortunately enough, in the release 1.2.2 we fixed a leak (thanks Russel!) in the VLArrays that prevented its use to keep a large number of rows. Now, you can expect that VLArrays would work just fine. > * Maybe I could have all of my strings (e.g. 10 strings all probably < 50 > chars) be metadata on the Atoms of a VLArray - this seems a little confusing, > and probably not as efficient... Uh... I don't understand you very well here. At any rate, Atoms itself cannot have associated metadata: you can only associate metadata to primary objects (Table or *Array). HTH, -- >0,0< Francesc Altet http://www.carabos.com/ V V Cárabos Coop. V. Enjoy Data "-" ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 _______________________________________________ Pytables-users mailing list Pytables-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pytables-users
