How to add a column between two columns?

I have a matrix 3x3 and a column vector 3x1. I'm trying to add the column vector between the second and third column of the 3x3 matrix.How can i add the column to the matrix?

M1=randi([-10,20],[3,3]); % M1 is 3x3 matrix

r=[5;5;5]; % r is 3x1 vector

Answer 1

[Adam Danz]

out = [M1(:,1:2), r, M1(:,3)];  

[C'lette]

I suggest a little change, just to avoid hardcoding:

out = [M1(:,1:2), r, M1(:,3:end)];