Before recent advances such as Cython, Boost.Python was one of the best ways to integrate C++ code into Python programs. The following C++ source code exposes a C++ function to Python. The function takes a NumPy array as an argument and extracts a C++ integer type.

#include "boost/python/extract.hpp"
#include "boost/python/numeric.hpp"

using namespace boost::python;

// Functions to demonstrate extraction
void setArray(boost::python::numeric::array data) {

	// Access a built-in type (an array)
	boost::python::numeric::array a = data;
	// Need to  array elements because their type is unknown
	std::cout << "First array item: " << extract(a[0]) << std::endl;

// Expose classes and methods to Python
	boost::python::numeric::array::set_module_and_type("numpy", "ndarray");
	def("setArray", &setArray);


2 thoughts on “Boost.python Numpy example

  1. I get this error :

    import TestNumpy as tnp
    ImportError: dynamic module does not define init function (initTestNumpy)


  2. Hi ,

    I get the error “Segmentation fault: 11”

    when i run the python code after compiling above c++ code

    #————— #

    import TestNumPy as nt
    import numpy as np
    a = np.array([10,20,30])


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