title: Appropriate data structure for table that uses ranges
body: <p>I have a table that looks like this:</p>
  
  <pre><code>       &lt;22  23-27   
  8-10   1.3   1.8
  11-13  2.2   2.8
  14-16  3.2   3.8
  </code></pre>
  
  <p>and it goes on. So I'd like to lookup a value like this:</p>
  
  <pre><code>lookup(11,25)
  </code></pre>
  
  <p>and get the response, in this case 2.8. What is the best data structure to use for this? I have the data in CSV format. </p>
  
  <p>I'm looking to program this in PHP.</p>
  
  <p>Thank you.</p>