title: How do I inner join two array in numpy?
body: <p>I have two array looks like this:</p>
  
  <h3>A:</h3>
  
  <pre><code>20131010 123 12321 12312312
  20131011 123 12321 12312312
  20131012 123 12321 12312312
  20131013 123 12321 12312312
  </code></pre>
  
  <h3>B:</h3>
  
  <pre><code>20131010 bbbb sad sadsad
  20131011 asd asdd asdad
  20231012 123 12321 12312312
  20141013 123 12321 12312312
  20141023 123 12321 12312312
  </code></pre>
  
  <p>Now I need to inner join these two array by the first column(date), the result should looks like this:</p>
  
  <pre><code>20131010 123 12321 12312312 bbbb sad sadsad
  20131011 123 12321 12312312 asd asdd asdad
  </code></pre>
  
  <p>How do I make it ? Note that each have lots of columns so I can't name every column, but the compare column is indeed only one.</p>