title: Python after detecting the ranking of array how to delete the column that is rubbish
body: <p>It's known that we can use the library to detect the array:</p>
  
  <p>matrix_rank(A)</p>
  
  <p>Then it will return the rank of this matrix. I got my rank for A is : 1450</p>
  
  <p>However, it's in fact 1465 columns in the array. Then my problem is: how to delete those 15 columns that are the rubbish of this array? Is there any way to solve this issue?</p>
  
  <p>Like for example,</p>
  
  <pre><code>G = [ -1  0  0  0 ]   
      [  0 -1  0  0 ]       
      [  0  0 -1 -1 ]       
      [ -1 -1  0  0 ]    
  </code></pre>
  
  <p>The last column is rubbish because it's the sum of the first two lines.</p>
  
  <p>So is there any library that can help us to delete the column in python?   </p>