On 24 September 2012 02:39, JBT <jianbao....@gmail.com> wrote: > Hi, > > I am looking for a way to pass numeric arrays, such as *float a[100]; > double b[200];*, from C extension codes to python. The use case of this > problem is that you have data stored in a particular format, NASA common > data format (CDF) in my case, and there exists an official C library to > read/create/edit such data, and you want to do data analysis in python. The > problem comes down to how to feed the data into python. >
You probably want to wrap the c arrays in numpy.ndarray objects that can then be accessed manipulated from Python. Numpy has a function that (I think) does what you want called PyArray_SimpleNewFromData: http://docs.scipy.org/doc/numpy/reference/c-api.array.html#PyArray_SimpleNewFromData I recommend using Cython to create any extension modules that interact with C libraries. In Cython you can: 1) Use the above function to create a numpy array. 2) Manipulate c-pointers directly to extract their data and insert it into a standard Python container. 3) Write a simple extension type to wrap the pointer into an array type that is accessible from Python. In any case it seems that someone has already made a Python library for accessing CDF data, called pycdf (I have no experience of using this library): http://spacepy.lanl.gov/doc/pycdf.html Oscar
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