Creat list of list in the boost python

Question

I want to create a list of list using boost::python::list.

I tried this code but it seems the sub list does not have append function!

boost::python::list array;
boost::python::list temp;


for (int i = 0; i < max; i++)
        {
            array.append(temp);
            for (int j = 0; j < max; j++)
            {
                array[i].append(0); //error! array[i] does not have "append" member
            }
        }

Error message:

error: ‘boost::python::api::object_item’ has no member named ‘append’
       distArray[i].append(0);

Answer 1

You can append directly to temp.

boost::python::list array;
for (int i = 0; i < max; i++){
    boost::python::list temp;
    for (int j = 0; j < max; j++){
        temp.append(0);
    }
    array.append(temp);
}

Since list can hold anything, you get back a generic object when you pull it back out as array[i]. In c++ you need to know the type. Just adding a typecast is enough to satisfy the compiler, but would be risky if anything else can get in there. Boost python has conversion check functions if you need to work on the list later.