Advanced Python Programming

Typed memoryviews

C and NumPy arrays as well as the built-in bytes, bytearray, and array.array objects are similar in the sense that they all operate on a contiguous memory area (also called memory buffer). Cython provides a universal interface--the typed memoryview--that unifies and simplifies the access to all these data types.

A memoryview is an object that maintains a reference on a specific memory area. It doesn't actually own the memory, but it can read and change its contents; in other words, it is a view on the underlying data. Memoryviews can be defined using a special syntax. For example, we can define a memoryview of int and a  two-dimensional memoryview of double in the following way:

    cdef int[:] a     cdef double[:, :] b 

The same ...