[SciPy-User] List to record array problems, questions

Vincent Davis vincent@vincentdavis....
Tue Feb 23 23:18:04 CST 2010


I must be missing something simple. I have a list of lists data = "[['  0',
'  0', '234.0', '24.0', ' 25'], ['  1', '  0', '22428.0', '2378.1', '
25'],......" and what to make a record array (I guess I have made a
structured array) from it but it gets screwed up or I don't get it, likely
both.
Notice that at this stage the items are strings, not numbers, and there is
whitespace not sure this matters.

Here is what is happening, notice that the number get screwed up in the
structured array (not sure who to get a record array, I thought this was but
was told it is not)
adata = numpy.array(data,numpy.float64)

>>> adata
array([[  0.00000000e+00,   0.00000000e+00,   2.34000000e+02,
          2.40000000e+01,   2.50000000e+01],
       ...,
       [  4.77000000e+02,   4.77000000e+02,   2.07000000e+02,
          4.58000000e+01,   2.50000000e+01]])

This is what I would expect except it is not a record array.

This is not what I expect. I think I have tried every iteration including
using numpy dtaypes numpy.int32 or bdata = numpy.array(data, dtype = [('x',
int),('y', int),('mean',float),('stdv',float),('npixcels',int)])
What am I missing?

bdata = numpy.array(data, [('x', int),('y',
int),('mean',float),('stdv',float),('npixcels',int)])
>>> bdata
array([[(3153952, 0, 0.0, 0.0, 0), (3153952, 0, 0.0, 0.0, 0),
        (206933603122, 0, 0.0, 0.0, 0), (808334386, 0, 0.0, 0.0, 0),
        (3486240, 0, 0.0, 0.0, 0)],
       [(3219488, 0, 0.0, 0.0, 0), (3153952, 0, 0.0, 0.0, 0),
        (13561617777439282, 0, 0.0, 0.0, 0),
        (54074581398322, 0, 0.0, 0.0, 0), (3486240, 0, 0.0, 0.0, 0)],
       [(3285024, 0, 0.0, 0.0, 0), (3153952, 0, 0.0, 0.0, 0),
        (206933931058, 0, 0.0, 0.0, 0), (925775666, 0, 0.0, 0.0, 0),
        (3486240, 0, 0.0, 0.0, 0)],
       ...,
       [(3487540, 0, 0.0, 0.0, 0), (3618612, 0, 0.0, 0.0, 0),
        (206933602866, 0, 0.0, 0.0, 0), (908996661, 0, 0.0, 0.0, 0),
        (3486240, 0, 0.0, 0.0, 0)],
       [(3553076, 0, 0.0, 0.0, 0), (3618612, 0, 0.0, 0.0, 0),
        (13561596370041137, 0, 0.0, 0.0, 0),
        (62870573495603, 0, 0.0, 0.0, 0), (3486240, 0, 0.0, 0.0, 0)],
       [(3618612, 0, 0.0, 0.0, 0), (3618612, 0, 0.0, 0.0, 0),
        (206933798962, 0, 0.0, 0.0, 0), (942552372, 0, 0.0, 0.0, 0),
        (3486240, 0, 0.0, 0.0, 0)]],

      dtype=[('x', '<i8'), ('y', '<i8'), ('mean', '<f8'), ('stdv', '<f8'),
('npixcels', '<i8')])


  *Vincent Davis
720-301-3003 *
vincent@vincentdavis.net
 my blog <http://vincentdavis.net> |
LinkedIn<http://www.linkedin.com/in/vincentdavis>
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