title: filter dataframe rows based on length of column values
body: <p>I have a pandas dataframe as follows:</p>
  
  <pre><code>df = pd.DataFrame([ [1,2], [np.NaN,1], ['test string1', 5]], columns=['A','B'] )
  
  df
                A  B
  0             1  2
  1           NaN  1
  2  test string1  5
  </code></pre>
  
  <p>I am using pandas 0.20. What is the most efficient way to remove any rows where 'any' of its column values has length > 10? </p>
  
  <p>len('test string1')
  12</p>
  
  <p>So for the above e.g., I am expecting an output as follows:</p>
  
  <pre><code>df
                A  B
  0             1  2
  1           NaN  1
  </code></pre>