title: pandas filtering and column boolean operation in one line possible?
body: <p>I would like to reduce to a single line the following filtering of a pandas dataframe</p>
  
  <p>First an example DF:</p>
  
  <pre><code>dff = pd.DataFrame({'myfiltercol':[1,1,1,2,2],
                      'D':[True,False,True,False,True],
                      'E':[False,True,False,True,False]})
  
  print(dff)
  
    myfiltercol      D      E
  0            1   True  False
  1            1  False   True
  2            1   True  False
  3            2  False   True
  4            2   True  False
  </code></pre>
  
  <p>Now for the case in which myfiltercol = 1 I would like to make the boolean operation OR between column values of D and E and see if all the values are true.</p>
  
  <p>I was able to it like this in two lines:</p>
  
  <pre><code>dff2   = dff.loc[(dff['myfiltercol'] == 1),['D','E']]
  result = all(dff2['D'] | dff2['E'])
  </code></pre>
  
  <p>For some reason I need a one liner.
  Someone knows how?</p>
  
  <p>thanks.</p>