This is a basic MATLAB operation. It is for instructional purposes.
What if you are dealing with a matrix. Often you will want the row and column location of an element, or set of elements. For instance:
[0 1 0 0 0 0]
You might want
row = 1 col = 2
[0 1 1 1 0 0]
row = [2 1 1]
col = [1 2 3]
Check out Find to learn to do this.
Given a matrix, M, return the column vectors that represent the row and column indices, r and c, where the given matrix, M is greater than the threshold value, thresh. R and C will be combined into matrix out.