I should clarify what I meant...... Suppose I have a recarray with 50 fields and want to read just one of those fields. PyTables/HDF will read in the compressed data for chunks of complete rows, decompress the full 50 fields, and then give me back the data for just one field.
I'm after a solution where asking for a single field reads in the bytes for just that field from disk and decompresses it. This is similar to the difference between databases storing their data as rows or columns. See for example Mike Stonebraker's C-store column-oriented database (http://db.lcs.mit.edu/projects/cstore/vldb.pdf). Stephen Francesc Alted wrote: > A Friday 30 October 2009 14:18:05 Stephen Simmons escrigué: > >> - Pytables (HDF using chunked storage for recarrays with LZO >> compression and shuffle filter) >> - can't extract individual field from a recarray >> > > Er... Have you tried the ``cols`` accessor? > > http://www.pytables.org/docs/manual/ch04.html#ColsClassDescr > > Cheers, > > _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
