Hi, I'll just comment on the creation of your dtype:
> dt = [("<f8", "<f8")] You are creating a dtype with one field called '<f8' and with type '<f8': >>> dt = [("<f8", "<f8")] >>> dty = np.dtype(dt) >>> dty.names ('<f8',) What you may want are two fields with type '<f8' and without fieldname: >>> dt = [("<f8", "<f8")] >>> dty = np.dtype(('<f8,<f8')) >>> dty.names ('f0', 'f1') >>> dty.descr [('f0', '<f8'), ('f1', '<f8')] I can't help you with the json-module and what it's doing there. As the output is unequal to the input, I suspect JSON to be misbehaving here. If you need to store the dtype as strings, not as binary pickle, you can use pickle.dumps and pickle.loads _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion