title: pandas remove seconds from datetime index
body: <p>I have a pandas dataFrame called 'df' as follows</p>
  
  <pre><code>                       value    
  2015-09-27 03:58:30    1.0  
  2015-09-27 03:59:30    1.0  
  2015-09-27 04:00:30    1.0  
  2015-09-27 04:01:30    1.0
  </code></pre>
  
  <p>I just want to strip out the seconds to get this</p>
  
  <pre><code>                       value    
  2015-09-27 03:58:00    1.0  
  2015-09-27 03:59:00    1.0  
  2015-09-27 04:00:00    1.0  
  2015-09-27 04:01:00    1.0
  </code></pre>
  
  <p>How can i do this?</p>
  
  <p>ive tried things like</p>
  
  <pre><code>df.index.to_series().apply(datetime.replace(second=0, microsecond=0))
  </code></pre>
  
  <p>but i always get errors </p>
  
  <pre><code>TypeError: descriptor 'replace' of 'datetime.datetime' object needs an argument
  </code></pre>