[Cython] __next__ | not being able to use cpdef

[Aaron DeVore]

Out of curiosity, would most of the time be spent on the line "return
self.obj[self.i]"? It seems like a __getitem__ call would be much
slower than anything else in the class.

-Aaron

On Sat, Dec 6, 2008 at 11:39 PM, Stefan Behnel <stefan_ml at behnel.de> wrote:
> Hi,
>
> Jelle Feringa wrote:
>> cdef class FastLoopObj1d:
>>
>>     cdef int N, i
>>     cdef object obj
>>
>>     def __init__(self, n, obj ):
>>         self.N = n-1
>>         self.i = 0
>>         self.obj = obj
>>
>>     def __iter__(self):
>>         return self
>>
>>     # no cpdef allowed?
>>     def __next__( self ):
>>         if self.i < self.N:
>>             self.i+=1
>>             return self.obj[self.i]
>>         else:
>>             raise StopIteration
>>
>> I noticed that the cython iterator is about twice as fast compared to
>> the python version, when indexing an iterable object.
>> A respectable speedup, given how trivial the implementation is. Would
>> you consider the implementation optimal? Is this the fastest way of
>> indexing an iterable object?
>
> This looks a bit like a stripped down version of itertools.islice() to me.
> Have you tried that instead?
>
> Stefan
>
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