title: Non-continuous range in OpenCV
body: <p>I need to select all rows except one from OpenCV matrix. What I came up with is to select rows from two ranges (from 0 to i and from i + 1 to matrix.rows) and concatenate them to a new matrix.</p>
  
  <p>But this solution seems very dirty: concatenation copies the data to a new matrix, which I don't need. Moreover, when i = 0 or matrix.rows, an error occurs during concatenation, because one of the submatrices becomes empty, so this case should be handled separately. All this issues cause too much pain, and what I need is a more elegant solution.</p>