[Pytables-users] createTable chokes on rich-dtype structured array

[Alvaro T. C. <al...@mi...>]

Hi,

In view of the upcoming release I thought I'd report this because at
the time I cannot fix it myself:

I am using a structured array with a dtype specified with the
following numpy-accepted
format (quotation follows from
http://docs.scipy.org/doc/numpy/reference/arrays.dtypes.html):

[(field_name, field_dtype, field_shape), ...]

obj should be a list of fields where each field is described by a
tuple of length 2 or 3. (Equivalent to the descr item in the
__array_interface__ attribute.)

The first element, field_name, is the field name (if this is '' then a
standard field name, 'f#', is assigned). The field name may also be a
2-tuple of strings where the first string is either a “title” (which
may be any string or unicode string) or meta-data for the field which
can be any object, and the second string is the “name” which must be a
valid Python identifier.

This is my concrete example:

header = [(('timestamp', 't'), 'u4'),
               (('unit (cluster) id', 'unit'),'u2')]

This is what PyTables says upon passing either the structured array or
np.dtype(header) to the createTables function:

> test.createTable('/', 'spike', s, 'test')

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/home/tejero/Dropbox/O/ridge/doc/<ipython-input-40-5fdbd9feb41d> in <module>()
----> 1 test.createTable('/', 'spike', s, 'test')

/home/tejero/Local/Envs/test/lib/python2.7/site-packages/tables/file.pyc
in createTable(self, where, name, description, title, filters,
expectedrows, chunkshape, byteorder, createparents)
    768                      description=description, title=title,
    769                      filters=filters, expectedrows=expectedrows,
--> 770                      chunkshape=chunkshape, byteorder=byteorder)
    771
    772

/home/tejero/Local/Envs/test/lib/python2.7/site-packages/tables/table.pyc
in __init__(self, parentNode, name, description, title, filters,
expectedrows, chunkshape, byteorder, _log)
    805                     self._v_recarray = nparray
    806                 self.description, self._rabyteorder = \
--> 807                                   descr_from_dtype(nparray.dtype)
    808
    809         # No description yet?


/home/tejero/Local/Envs/test/lib/python2.7/site-packages/tables/description.pyc
in descr_from_dtype(dtype_)
    723     fields = {}
    724     fbyteorder = '|'
--> 725     for (name, (dtype, pos)) in dtype_.fields.items():
    726         kind = dtype.base.kind
    727         byteorder = dtype.base.byteorder

ValueError: too many values to unpack

-á.