title: tf.newaxis operation in TensorFlow
body: <p><code>x_train = x_train[..., tf.newaxis].astype(&quot;float32&quot;)</code></p>
  <p><code>x_test = x_test[..., tf.newaxis].astype(&quot;float32&quot;)</code></p>
  <p>Can someone please explain how <code>tf.newaxis</code> works ?</p>
  <p>I found a brief mention in the documentation</p>
  <p><a href="https://www.tensorflow.org/api_docs/python/tf/strided_slice" rel="noreferrer">https://www.tensorflow.org/api_docs/python/tf/strided_slice</a></p>
  <p>but I could not properly understand.</p>