On 03/05/15 22:52, Jeroen Demeyer wrote:
> On 2015-05-03 22:47, Vincent Delecroix wrote:
>> Hello,
>>
>> How do we convert Python object to a C long in Cython? The following
>> does not work properly as rationals or float gets converted (to their
>> floor)
>>
> In Cython, you call PyNumber_Index():
>
> from cpython.number cimport PyNumber_Index
> def f(u):
> cdef long u_long = PyNumber_Index(u)
Thanks!
If u is an instance of an extension class that properly defines
__index__, does the above call avoids the creation of an intermediate
Python int? I wonder because its signature is
PyObject* PyNumber_Index(PyObject *o)
If not, then the following would be faster for u being a Sage integer
isn't it
def f(u):
if type(u) is Integer:
if mpz_fits_slong_p((<Integer>u).value):
u_long = mpz_get_si((<Integer>u).value)
...
Vincent
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