title: Create an interval - Base R
body: <p>I would like to create a single interval without using the <code>cut</code> function.  For example, given integers <code>a</code> and <code>b</code> an interval <code>(a,b]</code> can be created by calling <code>cut(c(a, 2 * b - a), 2)[1]</code>:</p>
  
  <pre><code>a &lt;- 2.10
  b &lt;- 2.15
  intervals = cut(c(a, 2 * b - a), 2)
  intervals[1]
  #&gt; [1] (2.1,2.15]
  #&gt; Levels: (2.1,2.15] (2.15,2.2]
  </code></pre>
  
  <p>How can I create <code>(a,b]</code> without this workaround? I haven't been able to find any documentation for intervals outside of the documentation for the <code>cut</code> and <code>findInterval</code> functions.</p>