How to vectorize the following code?

I have an nx1 array f and a 3xm array g. I want to carry out the following insertion, where I pick index pairs from the first two rows of g and values from the last row of g:

for int i = 1:m
    f(g(1:2,i)) = g(3,i);
end

How can I vectorize the above code? The simple

f(g(1:2,:)) = g(3,:)

does not work and returns the following error

Unable to perform assignment because the left and right sides have a different
number of elements.

Any suggestions?

Answer 1

[Walter Roberson]

f(g(1:2,:)) = g([3 3], :);

[Jordan Tryggvesson]

Thanks for your answer! Could you confirm whether the following also works? It is very similar in spirit to my

question, so I think it makes sense to ask in a comment. Say that g is instead 4xm and I want to calculate

for int i = 1:m
    f(g(1:2,i)) = g(3,i)*g(4,i);
end

Then the following works, right?

f(g(1:2,:)) = g([3 3], :).*g([4 4],:);

[Walter Roberson]

Looks okay. Another way would be

f(g(1:2,:)) = kron([1;1], g(3,:).*g(4,:));

[Jordan Tryggvesson]

Alright, thanks for the help!