Can't get iterator in the C API

[MRAB]

On 2022-02-09 01:12, Jen Kris via Python-list wrote:
> I am using the Python C API to load the Gutenberg corpus from the nltk library and iterate through the sentences.  The Python code I am trying to replicate is:
> 
> from nltk.corpus import gutenberg
> for i, fileid in enumerate(gutenberg.fileids()):
>          sentences = gutenberg.sents(fileid)
>          etc
> 
> where gutenberg.fileids is, of course, iterable.
> 
> I use the following C API code to import the module and get pointers:
> 
> int64_t Call_PyModule()
> {
>      PyObject *pModule, *pName, *pSubMod, *pFidMod, *pFidSeqIter,*pSentMod;
> 
>      pName = PyUnicode_FromString("nltk.corpus");
>      pModule = PyImport_Import(pName);
> 
>      if (pModule == 0x0){
>          PyErr_Print();
>          return 1; }
> 
>      pSubMod = PyObject_GetAttrString(pModule, "gutenberg");
>      pFidMod = PyObject_GetAttrString(pSubMod, "fileids");
>      pSentMod = PyObject_GetAttrString(pSubMod, "sents");
> 
>      pFidIter = PyObject_GetIter(pFidMod);
>      int ckseq_ok = PySeqIter_Check(pFidMod);
>      pFidSeqIter  = PySeqIter_New(pFidMod);
> 
>      return 0;
> }
> 
> pSubMod, pFidMod and pSentMod all return valid pointers, but the iterator lines return zero:
> 
> pFidIter = PyObject_GetIter(pFidMod);
> int ckseq_ok = PySeqIter_Check(pFidMod);
> pFidSeqIter  = PySeqIter_New(pFidMod);
> 
> So the C API thinks gutenberg.fileids is not iterable, but it is.  What am I doing wrong?
> 
Look at your Python code. You have "gutenberg.fileids()", so the 
'fileids' attribute is not an iterable itself, but a method that you 
need to call to get the iterable.