title: how to reset index pandas dataframe after dropna() pandas dataframe
body: <p>I"m not sure how to reset index after dropna() </p>
  
  <pre><code>df_all = df_all.dropna()
  
  df_all.reset_index(drop=True)
  </code></pre>
  
  <p>but after drop row index  would skip  for example jump from 0,1,2,4  ..</p>