Bill Allombert on Wed, 21 Oct 2015 22:51:06 +0200


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Re: Using forvec as fordiv


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]

Cheers,
Bill.