PyTables example

pytables_examples.py

import tables

def make_h5_file(dat, filename, colname, n_rows):
    """Make a new HDF5 table to hold numpy array data ``dat``
    """
    filters = tables.Filters(complevel=5, complib='zlib')
    h5 = tables.openFile(filename, mode='w', filters=filters)
    
    h5shape = (0,) + dat.shape[1:]
    h5type = tables.Atom.from_dtype(dat.dtype)
    h5.createEArray(h5.root, 'data', h5type, h5shape, title=colname,
                    expectedrows=n_rows)
    h5.close()

def append_h5_file(dat, filename):
    """Append data to an existing HDF5 table
    """
    h5 = tables.openFile(filename, mode='a')
    h5.root.data.append(dat)
    h5.close()

def read_h5_file(h5_slice, filename):
    """Read a slice of an HDF5 file"""
    h5 = tables.openFile(filename)
    dat = h5.root.data[h5_slice]
    h5.close()
    return dat