title: Pandas - Sorting a dataframe by using datetimeindex
body: <p>The following is my dataframe which holds values from multiple Excel files. I wanted to do a time series analysis, so I made the index as <code>datetimeindex</code>. But my index is not arranged according to the date. The following is my dataframe:</p>
  
  <pre><code>    Item Details    Unit    Op. Qty Price   Op. Amt.    Cl. Qty Price.1 Cl. Amt.
  Month                               
  2013-04-01  5 In 1  Pcs -56.0   172.78  -9675.58    -68.0   175.79  -11953.96
  2013-04-01  Adaptor Pcs -17.0   9.00    -152.99 -17.0   9.00    -152.99
  2013-04-01  Agro Tape   Pcs -2.0    26.25   -52.50  -2.0    26.25   -52.50
  ...
  2014-01-01  12" Angal   Pcs -6.0    31.50   -189.00 -6.0    31.50   -189.00
  2014-01-01  13 Mm Electrical Drill Check    Set -1.0    247.50  -247.50 -1.0    247.50  -247.50
  2014-01-01  14" Blad    Pcs -5.0    157.49  -787.45 -5.0    157.49  -787.45
  ...
  2013-09-01  Zinc Bolt 1/4 X 2"(box) Box -1.0    899.99  -899.99 -1.0    899.99  -899.99
  2013-09-01  Zorik 88 32gram Pcs -1.0    45.00   -45.00  -1.0    45.00   -45.00
  2013-09-01  Zorrik 311 Gram Pcs -1.0    270.01  -270.01 -1.0    270.01  -270.01
  </code></pre>
  
  <p>It is not sorted according to the date. I wanted to sort the index and its respective rows also. I googled it and found that there is a way to sort the datetimeindex and is as follows:</p>
  
  <pre><code>all_data.index.sort_values()
  
  DatetimeIndex(['2013-04-01', '2013-04-01', '2013-04-01', '2013-04-01',
             '2013-04-01', '2013-04-01', '2013-04-01', '2013-04-01',
             '2013-04-01', '2013-04-01',
             ...
             '2014-02-01', '2014-02-01', '2014-02-01', '2014-02-01',
             '2014-02-01', '2014-02-01', '2014-02-01', '2014-02-01',
             '2014-02-01', '2014-02-01'],
            dtype='datetime64[ns]', name=u'Month', length=71232, freq=None)
  </code></pre>
  
  <p>But it is sorting only the index, how can I sort the entire <strong>dataframe</strong> according to the sorted index? Kindly help.</p>