dissecting a python dictionary

[AllinCottrell]

My C code wants an array of key:value pairs from the user, and the natural interface on the python side would seem to be a dictionary. The values must be of type string, int or float, each type needing specific handling. So in pybind11 I need to iterate over the dictionary checking the values. Here's my first attempt at "proof of concept" code:

#include <pybind11/pybind11.h>

namespace py = pybind11;

void python_dict_to_options (py::dict &d)
{
    py::list *dkeys = py::list(d.keys());
    py::list *dvals = py::list(d.values());
    int i, n = py::len(dvals);

    for (i=0; i<n; i++) {
        if (py::isinstance<py::str>(dvals[i])) {
            printf(" value is string\n");
        } else if (py::isinstance<py::int_>(dvals[i])) {
            printf(" value is int\n");
        } else if (py::isinstance<py::float_>(dvals[i])) {
            printf(" value is float\n");
        } else {
            printf(" value is none of the above\n");
        }
    }
}

This code fails to compile at the first hurdle, with the message

error: ‘class pybind11::dict’ has no member named ‘keys’

so clearly I've got the wrong idea. What is the right idea, please?

[AllinCottrell]

OK, I think I've got the idea now:

void python_dict_to_options (py::dict &d)
{
    for (auto &item : d) {
         if (py::isinstance<py::str>(item.second)) {
            printf(" value is string\n");
        } else if (py::isinstance<py::int_>(item.second)) {
            printf(" value is int\n");
        } else if (py::isinstance<py::float_>(item.second)) {
            printf(" value is float\n");
        } else {
            printf(" value is none of the above\n");
        }
    }
}