title: Want the last day of each month for a data frame in pandas
body: <p>I have a data frame in pandas where the index are business days. I want to create a new data frame using only the last day of each month, along with the corresponding data in the various columns. I have tried a few different ways with little success and the error message I keep getting is: AttributeError: 'DataFrame' object has no attribute 'date'.</p>
  
  <p>The index in my data frame is labeled 'Date'. Other than verifying that, I don't know where to go. Also, the dates in this column include hours, minutes, and seconds...not sure if that matters.</p>
  
  <p>Below is an example of what the data frame looks like:</p>
  
  <pre><code>Date                   A    B    C
  11/27/2015 00:00:00    5    2    4
  11/30/2015 00:00:00    2    9    1
  12/1/2015  00:00:00    6    1    8
  12/2/2015  00:00:00    4    7    0
  </code></pre>
  
  <p>I'd like for the result to show </p>
  
  <pre><code>11/30/2015 00:00:00    2  9  1
  </code></pre>
  
  <p>Some of the code I have tried is as follows: Got the same error with both.</p>
  
  <pre><code>prices = prices.resample('M', 'first')
  prices = prices.index + pd.offsets.MonthEnd(0)
  </code></pre>