Selecting required elements from a matrix

I have a matrix A which contains 1's and 0's I wish to construct a new matrix B such that it has all the i,j values where A(i,j)=1, i.e B will be 2 X N matrix with its elements as the indices of the elements in matrix A who have a value of 1. for eg: A=[1,0,1,1,0] then B={[1,1];[1,3];[1,4]} Thanks

[Matt J]

B={[1,1];[1,3];[1,4]} does not produce a 2xN matrix,

    >> B={[1,1];[1,3];[1,4]}

    B = 

        [1x2 double]
        [1x2 double]
        [1x2 double]

Answer 1

[Guillaume]

Is this what you're after ?

[row, col] = find(A);
B = [row col]';

I.e. use the two output version of find.

edit: The above answer assumes A is not a row vector. You can use Matt J fix to handle all cases or, if you know that A is a row vector:

[row, col] = find(A);
B = [row; col];

[Matt J]

Small fix, to handle the case when A is a row vector

 B = [row(:) col(:)].';

[Guillaume]

Oh yes, thanks!

I really hate that you can't write simple generic code in matlab because the shape of the output is not always the same.