title: quesion about the axis of tf.stack()
body: <p>I read the doc of <code>tf.stack()</code> on <a href="https://www.tensorflow.org/api_docs/python/tf/stack" rel="nofollow noreferrer">tensorflow stack </a>. There is an example on the page:</p>
  
  <pre><code>&gt;&gt;&gt; x = tf.constant([1, 4])
  &gt;&gt;&gt; y = tf.constant([2, 5])
  &gt;&gt;&gt; z = tf.constant([3, 6])
  &gt;&gt;&gt; sess=tf.Session()
  &gt;&gt;&gt; sess.run(tf.stack([x, y, z]))
  array([[1, 4],
         [2, 5],
         [3, 6]], dtype=int32)
  &gt;&gt;&gt; sess.run(tf.stack([x, y, z], axis=1))
  array([[1, 2, 3],
         [4, 5, 6]], dtype=int32)
  </code></pre>
  
  <p>what I don't understand is the second example where <code>axis=1</code>.</p>
  
  <p>From the result it seems it converts the three inputs rows to columns first </p>
  
  <p>and then put them toghter along the <code>axis=1</code>, but </p>
  
  <p>I think the result should be </p>
  
  <pre><code>array([[1,4, 2, 5, 3, 6 ]] dtype=int32 )
  </code></pre>
  
  <p>can anyone help explain this?</p>
  
  <p>Thanks!</p>