title: Test whether a variable equals either one of two values
body: <p>I want to test whether <code>a</code> equals 1 <strong>or</strong> 2</p>
  
  <p>I could do</p>
  
  <pre><code>a == 1 || a == 2
  </code></pre>
  
  <p>but this requires repeating <code>a</code> (which would be annoying for longer variables)</p>
  
  <p>I'd like to do something like <code>a == (1 || 2)</code>, but obviously this won't work</p>
  
  <p>I could do <code>[1, 2].include?(a)</code>, which is not bad, but strikes me as a <em>bit</em> harder to read</p>
  
  <p>Just wondering how do to this with idiomatic ruby</p>