title: Show value at the top of the bar with pandas
body: <p>I'm plotting a pandas dataframe group by a column, and would like to visualize it as a plot bar with the value at the top of it. Most of the examples I found are not straightforward and use matplotlib directly. What is the simple way to show the row value at the top of the bar?</p>
  
  <p>My dataframe looks like:</p>
  
  <hr>
  
  <pre><code>             |No. of Files|
  |reload_date|
  03/30/2019             86
  03/31/2019             96
  04/01/2019             78
  04/11/2019            320
  04/12/2019            357
  04/22/2019            460
  04/27/2019            498
  04/28/2019            565
  04/29/2019            913
  04/30/2019           1010
  05/01/2019           1428
  05/27/2019           1419
  05/28/2019           1477
  05/29/2019           1655
  </code></pre>
  
  <hr>
  
  <p>This works perflecty to plot the bar, but it is missing the value at the top.</p>
  
  <pre><code>files_per_date = data_set[['FileName','reload_date']]
  count_files = files_per_date.groupby(['reload_date']).count()
  ax = plotme.plot.bar(rot=0, subplots=True)
  
  
  plt.title("Files Reloaded per Day")
  plt.xlabel("Date of Reloading")
  plt.ylabel("Number of Files")
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/JqEqy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JqEqy.png" alt="enter image description here"></a>
  I tried to loop the sublots using this example:</p>
  
  <pre><code> for p in axtest.patches:
       axtest.annotate('{:.2E}'.format(Decimal(str(p.get_height()))), (p.get_x(), p.get_height()))
   plt.tight_layout()
  </code></pre>
  
  <p>I expect to have a numerical value at the top, like below
  <a href="https://i.stack.imgur.com/SUple.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SUple.png" alt="enter image description here"></a>
  but instead got this error:</p>
  
  <pre><code>  File "C:\Users\XXXX\AppData\Local\Programs\Python\Python37\lib\site-packages\pandas\core\indexes\base.py", line 3080, in get_loc
      return self._engine.get_loc(self._maybe_cast_indexer(key))
    File "pandas\_libs\index.pyx", line 140, in 
  pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\index.pyx", line 162, in 
  pandas._libs.index.IndexEngine.get_loc
    File "pandas\_libs\hashtable_class_helper.pxi", line 1492, in 
  pandas._libs.hashtable.PyObjectHashTable.get_item
    File "pandas\_libs\hashtable_class_helper.pxi", line 1500, in 
  pandas._libs.hashtable.PyObjectHashTable.get_item
  KeyError: 'reload_date'
  </code></pre>