title: MATLAB- how to read certain columns from a text file using an iterative manner
body: <p>I would like to read a csv file having an irregular matrix. 
  What I need to read is A column (Dates) and B column (Measurements) in an iterative manner. 
  Below is an example format. </p>
  
  <pre><code>       A, B, C,        A, B, C,        A, B, C   ...  ...                               
  4/1/1970, 2, 5, 3/1/1971, 6, 5, 2/1/1972, 7, 5   ...  ...
  7/1/1970, 3, 5, 7/1/1971, 2, 5, 4/1/1972, 3, 5   ...  ... 
          ,  ,  , 4/1/1971, 8, 5, 5/1/1972, 6, 5   ...  ... continued with this format
          ,  ,  ,         ,  ,  , 7/1/1972, 8, 5
          ,  ,  ,         ,  ,  , 8/1/1972, 11,5
  </code></pre>
  
  <p>Ultimately, I want to get </p>
  
  <pre><code>        A, B
   4/1/1970, 2
   7/1/1970, 3
   3/1/1971, 6       
   7/1/1971, 2
       .
       .
  </code></pre>
  
  <p>Can any experts help me? 
  Thank you in advance. </p>