Inserting elements in a vector

somdeb — Mon, 24 Sep 2007 15:27:29 -0400

I have a vector v1 of L1 elements. I need to insert elements of
another vector v2 of L2 elements (L2<L1) into known positions of v1.

What is the fastest way to do this? Right now I preallocate L1+L2
elements for v1 and for every position I have to insert a sample, I
right-shift all the elements of v1 to the right of that position and
then insert the value. This is taking a long time.

Re: Inserting elements in a vector

us — Mon, 24 Sep 2007 15:51:31 -0400

somdeb:
<SNIP vec acrobatics...

one of the many solutions

% the data
     v=1:10;
     w=[-10,-20,-30];
     pos=[2,6,7];
% the engine
     tf=false(1,numel(v)+numel(w));
     r=double(tf);
     tf(pos)=true;
     r(tf)=w;
     r(~tf)=v;
% the result
     r

us

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Inserting elements in a vector

Re: Inserting elements in a vector