How to assign parts of a matrix equal to a single vector

In matlab if you had a vector called y = ones(5,5), you could do the following assignments:

y(:,1) = 0; First column in all rows equals zero.

y(:,1:2) = 0; First two columns in all rows equals zero.

y(1,:) = 0; First row equals zero, etc.

But what if you wanted to be more specific, say for example I had a vector x = [0 2 0] and I wanted y(2:4,2:4) = x; Meaning the middle 3 columns and middle 3 rows would be set to that vector. The problem is it doesn't accept this kind of assignment and gives a "Subscripted assignment dimension mismatch" error. I was wondering if there is any way to do this, or this something like this only possible through a for loop?

Answer 1

[Richard Brown]

It's because y(2:4, 2:4) is a 3x3 matrix, and so you must assign it a 3x3 matrix. The command repmat is an easy way to stack multiple copies of a matrix together. Assuming you want each of the rows of that 3x3 block to be [0 2 0]:

x = [0 2 0];
y(2:4, 2:4) = repmat(x, 3, 1);