[Numpy-discussion] tostring() for array rows

josef.pktd@gmai... josef.pktd@gmai...
Fri Oct 9 14:05:36 CDT 2009


On Wed, Oct 7, 2009 at 1:20 PM, Christopher Barker
<Chris.Barker@noaa.gov> wrote:
> josef.pktd@gmail.com wrote:
>
>> I wanted to avoid the python loop and thought creating the view will be faster
>> with large arrays. But for this I need to know the memory length of a
>> row of arbitrary types for the conversion to strings,
>
> ndarray.itemsize
>
> might do it.
>
> -Chris

Thanks, (I forgot to reply), it works and feels less low level than strides.

Josef

>>> tmps2[0].itemsize * np.size(tmps2[0])
16
>>> tmp[0].itemsize * np.size(tmp[0])
24
>>> tmps2.strides[0]
16
>>> tmp.strides[0]
24
>>> tmp
array([[-1.414, -1.019, -1.171],
       [-1.273,  1.639, -0.854],
       [-1.795, -0.699,  0.595],
       [-0.865, -1.439, -0.275]])
>>> tmps2
array([(4.0, 0, 1), (1.0, 1, 3), (2.0, 2, 4), (4.0, 0, 1)],
      dtype=[('f0', '<f8'), ('f1', '<i4'), ('f2', '<i4')])
>>>



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