>> I'm writing a wrapper for sparse matrices (CSR format) and therefore >> need to store three vectors and 3 scalars: >> >> - data (float64 vector) >> - indices (int32 vector) >> - indptr (int32 vector) >> >> - nrows (int32 scalar) >> - ncols (int32 scalar) >> - nnz (int32 scalar) >> >> data and indices will always be the same length as each other (=nnz) >> but the indptr vector is much shorter. >> >> I've written routines that allow you to insert/update/delete rows or >> columns of the matrix by acting on these vectors only. However I'm >> struggling to work out the best pytables structure to store these, >> that allows me to append/insert/delete elements easily, and is >> efficient. >> >> I was using a Group with an EArray for each vector. This works ok but >> it seems like you are unable to delete items - is that correct? >> >> I also tried using a Group with a separate Table for each of the >> vectors (I could possibly just have two - one for data and indices and >> the other for indptr), but this seems to add a lot of overhead in >> manipulating the arrays. >> >> Is there something simple I'm missing? >> > > Hi Tom, > > It seems to me that what you want to be using is a Table, which supports a > lot of the functionality you desire, including removing rows (which EArrays > don't easily support) > http://pytables.github.com/usersguide/libref.html?highlight=remove#tables.Table.removeRows > . > > Rather than having a Group of EArrays, have a table whose columns represent > what you were storing in the EArrays. You should take a look at the Tables > tutorials to see how to do this: > http://pytables.github.com/usersguide/tutorials.html > > Be Well > Anthony > >
I think I've read those tutorials a dozen times over now .... As far as I can tell there is no way of inserting a row (as opposed to appending it to the end) - am I correct? I'm looking for the equivalent of numpy.insert Tom ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Pytables-users mailing list Pytables-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/pytables-users
