title: Use Lens as `map`
body: <p>I want to convert this line of code <code>map (^?! ix 0) [[0, 1], [4, 5], [9, 1]]</code> to entirely use lenses, so something like <code>[[0, 1], [4, 5], [9, 1]] &amp; each . ix 0</code>. However, the types don't match up. What is the correct way to do this?</p>