Python | Extension function operating on Arrays
Let’s write a C extension function that can operate on contiguous arrays of data, as might be created by the array module or libraries like NumPy and this function should be general purpose and not specific to any one array library.
The code should use Buffer Protocol to receive and process arrays in a portable manner. The code below is a C extension function that receives array data and calls the
avg(double *buf, int len) function from this article – Using C codes in Python.
Code #1 :
Code #2 : How this extension function works
Average : 2.0 Average numpy array : 2.0
Average list : Traceback (most recent call last): File "", line 1, in TypeError: 'list' does not support the buffer interface
PyBuffer_GetBuffer()function is the key to the code in the article.
- It tries to obtain the information about the memory representation in the given arbitrary Python object.
- It simply raises an exception and returns -1, if it is not possible to obtain information (as is the case with normal Python objects).
- The special flags passed to
PyBuffer_GetBuffer()give additional hints about the kind of memory buffer that is requested.
- As, PyBUF_ANY_CONTIGUOUS specifies that a contiguous region of memory is required.
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