Loop Over Python Dictionary (using C API) Twice?

Question

I'm currently writing a Python module in C. In it, I have a dictionary that I iterate over like so:

PyObject *key, *value;
Py_ssize_t pos = 0;

while (PyDict_Next(index, &pos, &key, &value))
    /* do interesting things here */

Later in the same method, I then want to loop over the dictionary again. However, PyDict_Next(...) continues to return NULL. Is there any way to reset the internal iteration counter used by PyDict_Next(...)?

Yup, looks like you are correct! I just discovered that a few hours ago, in fact. If you want to write that as an answer I'll accept it. :) — Matt Patenaude, Mar 05 '13 at 05:32

score 4 · Accepted Answer · answered Mar 05 '13 at 17:06

The iterator is initialized by setting pos to 0. You can restart the iterator by setting pos to 0 again.

PyObject *key, *value;
Py_ssize_t pos = 0;

while (PyDict_Next(index, &pos, &key, &value))
    /* do interesting things here */

pos = 0;

while (PyDict_Next(index, &pos, &key, &value))
    /* do even more interesting things here */

Loop Over Python Dictionary (using C API) Twice?

1 Answers1