> Given a certain value delta, I would like to get a subset of x, named > y, > where (y[i+1] - y[i]) >= delta
So in fact the problem is to find y such that (y[i(k)+n] - y[i(k)]) >= delta for n <= len(x) - 1 - i and i(0) = 0, i(k+1) = i(k) + n ? Well a loop or list comparison seems like a good choice to me. It is much more obvious at the expense of two LOCs. Did you profile the two possibilities and are they actually performance-critical? cheers Am Mittwoch, den 09.06.2010, 10:14 +0200 schrieb "V. Armando Solé": > That was my first thought, but that only warrants me to skip one point > in x but not more than one. > > >>> x= numpy.arange(10.) > >>> delta = 3 > >>> print x[(x[1:] - x[:-1]) >= delta] > [] > > instead of the requested [0, 4, 8] > > Armando > > Francesc Alted wrote: > > A Wednesday 09 June 2010 10:00:50 V. Armando Solé escrigué: > > > >> Well, this seems to be quite close to what I need > >> > >> y = numpy.cumsum((x[1:]-x[:-1])/delta).astype(numpy.int) > >> i1 = numpy.nonzero(y[1:] > y[:-1]) > >> y = numpy.take(x, i1) > >> > > > > Perhaps this is a bit shorter: > > > > y = x[(x[1:] - x[:-1]) >= delta] > > > > > > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
