title: Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex, but got an instance of 'Int64Index'
body: <p>I'm trying to resample this <strong><em>Timestamp</em></strong> column of this Dataframe:</p>
  
  <pre><code>  Transit.head():
  
        Timestamp                            Plate           Gate
    0 2013-11-01 21:02:17 4f5716dcd615f21f658229a8570483a8    65
    1 2013-11-01 16:12:39 0abba297ac142f63c604b3989d0ce980    64
    2 2013-11-01 11:06:10 faafae756ce1df66f34f80479d69411d    57
  </code></pre>
  
  <p>And Here's What I've Done:</p>
  
  <pre><code>  Transit.drop_duplicates(inplace=True)
    Transit.Timestamp = pd.to_datetime(Transit.Timestamp)
    Transit['Timestamp'].resample('1H').pad()
  </code></pre>
  
  <p>But I got This Error:</p>
  
  <pre><code>  Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex, but got an instance of 'Int64Index'
  </code></pre>
  
  <p>Any Suggestion Would Be Much Appreciated.</p>