Loïc Grenié on Thu, 22 Oct 2015 09:38:24 +0200


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Re: Using forvec as fordiv


On 2015-10-21 at 22:51 GMT+02:00 Bill wrote:
On Wed, Oct 21, 2015 at 04:41:47PM -0400, Charles Greathouse wrote:
> Given a vectors u and v with #v == #u, what's the easiest way to extract
> the elements of v for which the corresponding element of u is nonzero? (All
> elements from u will be 0 or 1.)

I suggest you look up vecextract.

? vecextract([1,2,3,4,5],fromdigits([1,0,1,0,1],2))
%1 = [1,3,5]

    Variant:

vecextract([1,2,3,4,5],select(x->x,[1,0,1,0,1],1))

     Hope this helps,

        Loïc