How can I change non zero values of a matrix into a value that increments for each element it is applied to.

I have a matrix A filled with zero's and non zero values. I wish to change all the non zero values of A into a unique number. To do this I thought of changing the first non zero value to 1 then the next to 2.. and so on until the end of the matrix is reached. I'm new to Matlab and not sure how to go about doing this.

I'm aware that I can use

    A(A!=0) = [x]

But I'm not sure how to set x up so it's a unique value each time.

Thanks.

[madhan ravi]

Can you give the example of your matrix?

[Jake Murkin]

The matrix represents the blue value of the RGB of an image. An example would be like this:

    A = [0 0 0 0 0 0;
      0 0 0 0 0 23;
      0 0 0 0 23 24;
      0 0 0 24 25 27;
      0 0 0 0 23 25;
      30 32 0 0 0 0;
      29 0 0 0 0 0;]

The matrix I'm working with is around 200x200 so this is just an example.

Answer 1

[Guillaume]

A(~A) = 1:sum(~A(:));

would do it.

[Stephen23]

1:nnz(~A)

[Guillaume]

Yes, even better!

A(~A) = 1:nnz(~A)