Re: How to copy data from a C array to a numpy array efficiently?

[Bradley Froehle]

Can you not just pass in your realData array to CDFlib, to avoid the copy in the first place?  Something like:

cimport numpy as np

import numpy as np

        cdef np.ndarray realData = np.zeros(np_shape, dtype='d')

        status = CDFlib(

                       SELECT_, zVAR_RECCOUNT_, numRecs,

                       NULL_)

        status = CDFlib(

                       GET_, zVAR_HYPERDATA_, <double*> realData.data,

                       NULL_)

[Chris Barker]

        status = CDFlib(

                       GET_, zVAR_HYPERDATA_, <double*> realData.data,

                       NULL_)

For the record, using .data may or may not be supported in future numpy releases. 

You can use realData[0] instead. And it saves you a typecast.

Also, if your lib does not support passing in a pointer, you can use memcpy() similarly.

Chris.

[Jianbao Tao]

Roger that. Thanks, Chris.