[Numpy-discussion] problem setting O type for datetime field in record arrays

[John Hunter]

I can create a record array with datetime types using fromrecords if I
don't specify a dtype and let numpy determine the dtype.  But when I
try and set the dtype at record array creation time, I get the error
below

In [17]: import numpy

In [18]: import datetime

In [19]: dt = datetime.datetime

In [20]: dt1 = dt.now()

In [21]: dt2 = dt.now()

In [22]: numpy.core.rec.fromrecords([[dt1, 0.5], [dt2, 1.0]],
names='date,height') Out[22]:
recarray([(datetime.datetime(2007, 6, 14, 13, 59, 20, 753356), 0.5),
       (datetime.datetime(2007, 6, 14, 13, 59, 22, 946850), 1.0)],
      dtype=[('date', '|O4'), ('height', '<f8')])

In [23]: numpy.core.rec.fromrecords([[dt1, 0.5], [dt2, 1.0]],
dtype=[('date', '|O4'), ('height', '<f8')])
------------------------------------------------------------
Traceback (most recent call last):
  File "<ipython console>", line 1, in ?
  File "/home/titan/johnh/dev/lib/python2.4/site-packages/numpy/core/records.py",
line 399, in fromrecords
    retval = sb.array(recList, dtype = descr)
ValueError: tried to set void-array with object members using buffer.


In [24]: numpy.__version__
Out[24]: '1.0.4.dev3868'