title: I am new to python and not able to understand " df_final=df_input[predictions.shape[0]*-1:]"
body: <p>Below is the code  in which df_final is a dataframe and df_input is filtering some columns but please suggest what is this called as</p>
  <pre><code>df_final=df_input[predictions.shape[0]*-1:]
  </code></pre>