Re: URGENT!! Referencing a matrix from another vector

one way would be to create a logical matrix, t= a==1. Then use repmat
to creat t2 = [t t]. Multiply t2 with b, i.e. c = t2.*b. Now you can
remove the rows with zeros, c(all(c,2)==0,:)=[]
While not elegant, I think it will do the job. (i'd love to know any
better ways there are)

sushma

charles benzinger wrote:


Hi,

This is a follow up to a question I posted earlier:

Suppose I have a 9x1 matrix a = [ 1 2 2 4 2 1 1 5 1]'. Let b=
rand(9,2).

I want to create matrix c (n x 2) matrix, where the first column in
c
are the elements in teh first column of b where a==1. I want the
second column to be elements in teh second column of b where a==1.

I have tried c = b(a==1), but that returns one column of outpur (it
stacks the two columns I want into one).
Any help would be appreciated!!!

cb
.

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