title: How to cut a txt to a matrix in python?
body: <p>I've got a txt which looks like this:</p>
  
  <pre><code>JB651 ACDCCADBCADCDA
  JB831 ACACCBBBBBDDAC
  JC124 DACBDBBACBDCDC
  JD329 BAACDBABCCDDAB
  JD830 BDDCDBABBBAAAD
  JI428 DCBCCBBBBCCCCA
  </code></pre>
  
  <p>And I have to cut it to a matrix (I would say first I have to count the lines for a <code>for</code> loop) looks like this:</p>
  
  <pre><code>[[JI428] [D,C,B,C,C,B,B,B,B,C,C,C,C,A]]
  </code></pre>
  
  <p>And then, how can I refer to any line or letter of the 2nd part? (I'm a totally beginer)</p>