title: How to remove a certain row or column while using Eigen Library c++
body: <p>I am using Eigen library for my project. I am searching how to remove a certain row or column from the given matrix in Eigen. I am not successful.</p>
  
  <pre><code>MatrixXd A = X1 X2 X3 X4
               Y1 Y2 Y3 Y4
               Z1 Z2 Z3 Z4
               A1 A2 A3 A4
  MatrixXd Atransform = X1 X2 X4
                        Y1 Y2 Y4
                        Z1 Z2 Z4
                        A1 A2 A4
  enter code here
  </code></pre>
  
  <p>other than iterating through whole matrix or by using block operations on matrix A . Is there a method to do it simply.</p>