MATLAB subtract every row of matrix by a given vector

Question

Let

M = | 1 2 3 |
    | 4 5 6 |
    | 7 8 9 |

and

V = | 1 1 1 |

I want to subtract V from every row of M so that M should look like

M = | 0 1 2 |
    | 3 4 5 |
    | 6 7 8 |

How can I do that without using a for, is there any straightforward command?

Answer 1

>> M = [1 2 3; 4 5 6; 7 8 9];
>> V = [1 1 1];
>> MV = M-repmat(V,size(M,1),1)

MV =

     0     1     2
     3     4     5
     6     7     8

The call to repmat repeats the vector V by the number of rows in M.

User beaker pointed out that an even simpler (though a bit obscure) syntax works in recent versions of MATLAB. If you subtract a vector from a matrix, MATLAB will extend the vector to match the size of the matrix as long as one dimension of vector matches the matrix dimensions. See Compatible Array Sizes for Basic Operations.

>> M-V

ans =

     0     1     2
     3     4     5
     6     7     8

Of course, if you know that V will contain all 1s, the solution is even simpler:

>> MV = M-1

MV =

     0     1     2
     3     4     5
     6     7     8