I found this very helpful question and answer: Return vector<pair<int,int>> & from c++ method to python list of tuples using swig typemap
However I have some problems iterating the return vector if it's not a reference, here the example:
myclass.h:
#include <vector>
#include <utility>
using std::vector;
using std::pair;
class MyClass {
private:
vector<pair<int,int> > _myvector;
public:
MyClass( );
const vector<pair<int,int> > & GetMyVector() const;
};
myclass.cpp:
#include "myclass.h"
MyClass::MyClass(): _myvector()
{_myvector.push_back(std::make_pair(1,2));_myvector.push_back(std::make_pair(1,2));};
const vector<pair<int,int>> & MyClass::GetMyVector() const {
return _myvector;
};
myclass.i:
%module x
%include <std_pair.i>
%include <std_vector.i>
%include <std_string.i>
%template() std::pair<int,int>;
%template(PairVector) std::vector<std::pair<int,int> >;
%{
#include "myclass.h"
%}
%include "myclass.h"
compiled with:
g++ -std=c++11 -c -fPIC myclass.cpp
swig -c++ -v -python myclass.i
g++ -std=c++11 -fPIC -c myclass.cpp myclass_wrap.cxx -I/usr/include/python2.7
g++ myclass.o myclass_wrap.o -shared -fPIC -o _x.so
but when I run something like this in python:
import x
b=x.MyClass()
print(b.GetMyVector())
for a,b in b.GetMyVector():
print(a,b)
then I get:
<Swig Object of type 'vector< std::pair< int,int >,std::allocator< std::pair< int,int > > > *' at 0x7ff06804b1b0>
Traceback (most recent call last):
File "Test.py", line 6, in <module>
for a,b in b.GetMyVector():
TypeError: 'SwigPyObject' object is not iterable
How can I iterate the returned vector properly in python? And why is a pointer to vector returned? Do I have to change something in the swig file?
In case it is relevant: (on Ubuntu)
- SWIG Version 2.0.11
- g++ (Ubuntu 4.9.4-2ubuntu1~14.04.1) 4.9.4
- Python 2.7.6
