On Sat, May 15, 2010 at 9:27 AM, Jimmie Houchin <jlhouc...@gmail.com> wrote: > On 5/15/2010 6:30 AM, josef.p...@gmail.com wrote: >> On Sat, May 15, 2010 at 12:24 AM, Jimmie Houchin<jlhouc...@gmail.com> wrote: >>> def getArray(instrument, weekString=None): >>> ... >>> cur.execute(sql) >>> weekData = cur.fetchall() >>> wdata = [] >>> lst = [] >>> dtminute, dttypes = createDType() >>> for i in dttypes: >>> if i[1] == 'f8': lst.append(0.0) >>> elif i[1] == 'i1': lst.append(0) >>> else: lst.append('') >>> for m in weekData: >>> data = list(m)+lst[9:] >>> wdata.append(data) >> >> I think "data" here should be a tuple, i.e. tuple(data) >> structured arrays expect tuples for each element/row >> >> If this is not it, then you could provide a mini example of wdata with >> just a few rows. >> >>> return np.array(wdata,dtype=dtminute) >>> >>> The createDType() function works fine. The getArray() function fails with: >>> ValueError: Setting void-array with object members using buffer. >> >> cryptic exceptions messages in array construction usually means there >> is some structure in the argument data that numpy doesn't understand, >> I usually work with trial and error for a specific example >> >> Josef > > Hello Josef, > > Wrapping data, tuple(list(m)+lst[9:]) > works. > > Thanks. > > For some reason I was under the impression that numpy accepted either > lists or tuples as long as the shape of the structure, and the data > types was the same as the dtype array structure that it is filling. > Is there a particular reason this is not so?
the tuple (row) is one element of the structured array. It's possible to have an n-dimensional structured array where each element is a tuple. So, I guess, numpy needs the distinction between list and tuples to know what is an element. That's from hitting at this very often, I never looked at the numpy internals for this. Josef > > Again, thanks. I can now get rid of my moderately less elegant, but > working second version. > > Jimmie > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion