PyTables¶

Automatically close already open hdf5 files before opening¶

for hdf5 in ['hdf5_read', 'hdf5_write', 'hdf5_append']:
    if hdf5 in globals():
        globals()[hdf5].close()

Generate a `hdf5` file from a recarray¶

hdf5 = tables.openFile('panel.hdf5', 'w')

filters = tables.Filters(complib='blosc', complevel=5)
table = hdf5.createTable('/', 'panel', panel, filters=filters)

Compress and Compacting PyTables files¶

http://www.pytables.org/docs/manual-1.4/apc.html#ptrepackDescr

PyTables includes a handy utility called ptrepack which can be very useful not only to compact fragmented files, but also to adjust some internal parameters in order to use better buffer and chunk sizes for optimum I/O speed.

$ ptrepack --complevel=5 --complib=blosc source.hdf5 target.hdf5

Modifying value in-place¶

http://permalink.gmane.org/gmane.comp.python.pytables.user/1703

In order to modify the value,

Use cols accessor:

table.cols.number[1] = 3

Use modifyRows() method:

row = table[1]
row['number'] = 3
table.modifyRows(1, rows=[row])