How to set all elements in a 2D Matrix between two indices to "1" in each row

I've a matrix A e.g. like this:

A =

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

And I want all elements between the "ones" per row to be "one" as well. The result should look like this: B =

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

If it helps, I also have two vectors with the indices of the first and second one.

Thanks!!

PS: If possible the solution would not use any loops since the real matrix that I have to use is very large and the program shall be very efficient.

Answer 1

[Alfonso Nieto-Castanon]

 cumsum(A,2)==1|A;

[Andrei Bobrov]

+1

[Tim]

A one liner..Perfect! Great work, thanks a lot!

Answer 2

[Andrei Bobrov]

cumsum(A,2)>0 & fliplr(cumsum(A(:,end:-1:1),2))>0

[Wayne King]

How you come up with some of these solutions Andrei! :)

[Tim]

Nice Solution as well! Thanks!

Answer 3

[sixwwwwww]

you can do it as follow:

   for i = 1:size(A, 1)
       idx = find(A(i, :));
       A(i, min(idx):max(idx)) = 1;
   end

[Tim]

Nice, thanks! That helps. But is there a way to avoid the loop? E.g. use a vector that contains all the "idx" or so? Thanks!