title: pandas dataframe use np.where and drop together
body: <p>I have a dataframe and I'd like to be able to use np.where to find certain elements based on a given condition, and then use pd.drop to erase the elements corresponding to the index found with np.where.</p>
  
  <p>I.e., </p>
  
  <pre><code>idx_to_drop = np.where(myDf['column10'].isnull() | myDf['column14'].isnull())
  myDf.drop(idx_to_drop)
  </code></pre>
  
  <p>But I get a value error since drop does not take numpy array indexes.  Is there a way to achieve this using np.where and some drop function in pandas?</p>