title: Mapping a nested list with List Comprehension in Python?
body: <p>I have the following code which I use to map a nested list in Python to produce a list with the same structure. </p>
  
  <pre><code>&gt;&gt;&gt; nested_list = [['Hello', 'World'], ['Goodbye', 'World']]
  &gt;&gt;&gt; [map(str.upper, x) for x in nested_list]
  [['HELLO', 'WORLD'], ['GOODBYE', 'WORLD']]
  </code></pre>
  
  <p>Can this be done with list comprehension alone (without using the map function)?</p>