[Numpy-discussion] Simple problem. Is it possible without a loop?

"V. Armando Solé" sole@esrf...
Wed Jun 9 03:00:50 CDT 2010


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)

Sorry for the time taken!

Best regards,

Armando

V. Armando Solé wrote:
> Hello,
>
> I am trying to solve a simple problem that becomes complex if I try to 
> avoid looping.
>
> Let's say I have a 1D array, x,  where x[i] <= x[i+1]
>
> Given a certain value delta, I would like to get a subset of x, named y, 
> where (y[i+1] - y[i]) >= delta
>
> In a non-optimized and trivial way, the operation I would like to do is:
>
> y=[x[0]]
> for value in x:
>     if (y[-1] -value) < delta:
>        y.append(value)
> y=numpy.array(y)
>
> Any hint?
>
> Best regards,
>
> Armando
>
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