Re: [Numpy-discussion] Inverted indices

2014-08-07 Thread Nicolas P. Rougier
Oh thanks, I would never have imagined a one-line solution... Here are the benchmarks: In [2]: %timeit stefan(S) 10 loops, best of 3: 10.8 µs per loop In [3]: %timeit gregor(S) 1 loops, best of 3: 48.1 µs per loop In [4]: %timeit gregor2(S) 10 loops, best of 3: 3.23 µs per loop

Re: [Numpy-discussion] Inverted indices

2014-08-07 Thread Gregor Thalhammer
Am 07.08.2014 um 13:59 schrieb Gregor Thalhammer : > > Am 07.08.2014 um 13:16 schrieb Nicolas P. Rougier : > >> >> Hi, >> >> I've a small problem for which I cannot find a solution and I'm quite sure >> there is an obvious one: >> >> I've an array Z (any dtype) with some data. >> I've a (so

Re: [Numpy-discussion] Inverted indices

2014-08-07 Thread Gregor Thalhammer
Am 07.08.2014 um 13:16 schrieb Nicolas P. Rougier : > > Hi, > > I've a small problem for which I cannot find a solution and I'm quite sure > there is an obvious one: > > I've an array Z (any dtype) with some data. > I've a (sorted) array I (of integer, same size as Z) that tells me the index

Re: [Numpy-discussion] Inverted indices

2014-08-07 Thread Nicolas P. Rougier
Nice ! Thanks Stéfan. I will add it to the numpy 100 problems. Nicolas On 07 Aug 2014, at 13:31, Stéfan van der Walt wrote: > Hi Nicolas > > On Thu, Aug 7, 2014 at 1:16 PM, Nicolas P. Rougier > wrote: >> Here is a small example: >> >> Z = [(0,0), (1,1), (2,2), (3,3), (4,4)) >> I = [0,

Re: [Numpy-discussion] Inverted indices

2014-08-07 Thread Stéfan van der Walt
Hi Nicolas On Thu, Aug 7, 2014 at 1:16 PM, Nicolas P. Rougier wrote: > Here is a small example: > > Z = [(0,0), (1,1), (2,2), (3,3), (4,4)) > I = [0, 20, 23, 24, 37] > > S = [ 20,20,0,24] > -> Result should be [(1,1), (1,1), (0,0),(3,3)] > > S = [15,15] > -> Wrong (15 not in I) but ideally, I wo

[Numpy-discussion] Inverted indices

2014-08-07 Thread Nicolas P. Rougier
Hi, I've a small problem for which I cannot find a solution and I'm quite sure there is an obvious one: I've an array Z (any dtype) with some data. I've a (sorted) array I (of integer, same size as Z) that tells me the index of Z[i] (if necessary, the index can be stored in Z). Now, I have