Finally I'm able to use std::vector in python using the [] operator. The trick is to simple provide a container in the boost C++ wrapper which handles the internal vector stuff:
#include <boost/python.hpp>
#include <vector>
class world
{
std::vector<double> myvec;
void add(double n)
{
this->myvec.push_back(n);
}
std::vector<double> show()
{
return this->myvec;
}
};
BOOST_PYTHON_MODULE(hello)
{
class_<std::vector<double> >("double_vector")
.def(vector_indexing_suite<std::vector<double> >())
;
class_<World>("World")
.def("show", &World::show)
.def("add", &World::add)
;
}
The other challenge is: Howto translate python lists into std::vectors? I tried to add a c++ class expecting a std::vector as parameter and added the corresponding wrapper code:
#include <boost/python.hpp>
#include <vector>
class world
{
std::vector<double> myvec;
void add(double n)
{
this->myvec.push_back(n);
}
void massadd(std::vector<double> ns)
{
// Append ns to this->myvec
}
std::vector<double> show()
{
return this->myvec;
}
};
BOOST_PYTHON_MODULE(hello)
{
class_<std::vector<double> >("double_vector")
.def(vector_indexing_suite<std::vector<double> >())
;
class_<World>("World")
.def("show", &World::show)
.def("add", &World::add)
.def("massadd", &World::massadd)
;
}
But if doing so, I end up with the following Boost.Python.ArgumentError:
>>> w.massadd([2.0,3.0])
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
Boost.Python.ArgumentError: Python argument types in
World.massadd(World, list)
did not match C++ signature:
massadd(World {lvalue}, std::vector<double, std::allocator<double> >)
Can anybody tell me how I can access python lists within my c++ function?
Thanks, Daniel
To make your C++ method accept Python lists you should use boost::python::list
void massadd(boost::python::list& ns)
{
for (int i = 0; i < len(ns); ++i)
{
add(boost::python::extract<double>(ns[i]));
}
}