title: How to check if a key exists in an array of arrays?
body: <p>Is there a straightforward way to do something like the following without excessive looping?</p>
  
  <pre><code>myArray = [["a","b"],["c","d"],["e","f"]]
  if myArray.includes?("c")
     ...
  </code></pre>
  
  <p>I know this works fine if it's just a normal array of chars... but I would like something equally as elegant for an array of an array of chars (bonus points for helping convert this to an array of tuples).</p>