Delete last n1,n2,n3 (...) elements in each row in a Matrix in an efficient way or set to zero

I've a large set of data and i want to remove from the end of each row a different amount of elements (0-n). Is there a fast way to do this without using a loop?

As an example: A= % In reality different numbers, not only ones!

     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1

Then I've a vector saying how many elements to delete from each row, e.g.:

B =

     1     3     0     2     1

So the result would look like:

A2

     1     1     1     1     0
     1     1     0     0     0
     1     1     1     1     1
     1     1     1     0     0
     1     1     1     1     0

Thanks so much in advance!

Answer 1

[Roger Stafford]

 [m,n] = size(A);
 p = cumsum(accumarray([(1:m)',n+1-B'],1,[m,n+1]),2);
 A(p(:,1:n)==1) = 0;

Answer 2

[Image Analyst]

As long as you want to simply set to zero, no need to use cell arrays:

A=[...
     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1
     1     1     1     1     1]

B =[1     3     0     2     1];
for row = 1 : size(A, 2)
  A(row,(end-B(row)+1):end) = 0;
end
A % Print to command window.