title: Remove Minutes and Hours from Series
body: <p>Good Morning,</p>
  
  <p>I have the following Dataframe (Year, Month, Day, Hour, Sec):</p>
  
  <pre><code>print(df)
  
       Date               Price
  2018-01-02 09:42:00       2
  2018-01-02 09:46:00       4
  2018-01-02 10:22:00       6
  ...
  </code></pre>
  
  <p>I would like to get, without minutes and seconds:</p>
  
  <pre><code>print(final_df)
  
       Date               Price
  2018-01-02                2
  2018-01-02                4
  2018-01-02                6
  ...
  </code></pre>
  
  <p>I tried:</p>
  
  <pre><code>df['Date'] = datetime.datetime.strptime(df['Date'], '%Y-%m-%d').date()
  </code></pre>
  
  <p>But it reports <em>"strptime() argument 1 must be str, not Series"</em></p>