Thanks for your elaborate answer. I didn't realize that uint64 was not so standard (I work on Linux). Very good point. I will stick to signed ints for now.
And yes, it is not only the free beer that I appreciate! All the best, Gabriel On Tue, 2007-03-06 at 13:51 +0100, Francesc Altet wrote: > Well, this turns out to be a limitation of the numexpr package. Internally, > numexpr uses a limited set of types for doing calculations, and unsigned ints > are always upcasted to the immediate signed int that can fit the information. > The problem here is that there is not a (standard) signed int that can be > used to keep the information of an unsigned int64. In addition to this, you > will probably know that Win32 doesn't define such an uint64 type, so > supporting this in numexpr in a general way is not going to be easy in the > future (unless Win64 or Vista have introduced the uint64 type, but still, we > need several years until Win64/Vista will completely replace Win32). > > So, your best bet right now is to avoid UInt64 types if you can. If you > absolutely need UInt64, the only way for doing selections with this is using > regular python selections. For example, if your table has a 'colM' column > which is declared as an UInt64Col, then you can still filter its values with: > > [row['colN'] for row in table if row['colM'] < X] > > However, this approach will generally lead to slow speed (specially on Win32 > platforms, where the values will be converted to long python types). > > > All the best, and many thanks for making PyTables freely available, > > Well, it's not only freely available, it's also meant to be *free* (as in > freedom ;) software. > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Pytables-users mailing list Pytables-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pytables-users
