title: Select specific row and column by indexing on dataframe directly
body: <pre><code>d = {'col1': [33,34,35], 'col2': [5,6,8], 'col3': [7,8,9]}
  df = pd.DataFrame(data=d)
  df[['col1','col3']].head()
  </code></pre>
  
  <p>With the code above, I can select <code>col1</code> and <code>col3</code>, but if I wish to select only row 1 and row 3 (with value <code>[33,35]</code>, and <code>[7,9]</code>) without the usage of any function (e.g., <code>loc</code>, <code>iloc</code>, <code>at</code>, <code>iat</code> etc.) - purely using indexing on dataframe e.g., <code>df[..,..]</code>, is there a way to achieve that?</p>