title: How do I change all column values into a same value in Python's 2D-List?
body: <p><code>input_map = [ [ None for i in range(3) ] for j in range(3) ]</code></p>
  
  <p>Let's say I have a <code>3x3</code> list of <code>None</code> values.
  I would like to assign <code>2</code> to the 2nd column so that it becomes,</p>
  
  <p><code>[[None, 2, None],
    [None, 2, None],
    [None, 2, None]]</code></p>
  
  <p>I wonder if there is a way how to do this without using a <code>for</code> loop.</p>
  
  <p>I am not using libraries like <code>Pandas</code>. Just pure <code>Python</code>.</p>