title: OpenCV extract submatrix from certain positions
body: <p>Say I require to extract a submatrix with values on certain positions of another matrix. For example in matlab it work like this:</p>
  
  <p>extract = [1 3 4];
  dst = src(extract);</p>
  
  <p>Where src is one dimensional array, extract defines indices of values to extract, and dst is destination array which will keep values on indices 1, 3, 4 of array src.</p>
  
  <p>Is there any way to do the same in Opencv with variable of type cv::Mat assuming that it has only one row? Without looping through every element and just using function.</p>