title: Python - How to check list monotonicity
body: <p>What would be an <strong>efficient and pythonic</strong> way to check list monotonicity?<br> i.e. that it has monotonically increasing or decreasing values?</p>
  
  <p>Examples:</p>
  
  <pre><code>[0, 1, 2, 3, 3, 4]   # This is a monotonically increasing list
  [4.3, 4.2, 4.2, -2]  # This is a monotonically decreasing list
  [2, 3, 1]            # This is neither
  </code></pre>