title: How can I split a string into chunks?
body: <p>I have a VERY long string of numbers (1000 characters). I would like to break it down into chucks of 5 and insert into an array <code>arr</code>. </p>
  
  <pre><code>str = "7316717653133062491922511967442657474206326239578318016 ..."
  </code></pre>
  
  <p>I tried <code>each_slice</code> but when I attempt to <code>require 'enumerator'</code> #=> <em>irb says: false</em></p>
  
  <pre><code>str.each_slice(5).to_a
  </code></pre>
  
  <p>I would like the output to look like:</p>
  
  <pre><code>arr = [ "73167", "17653", "33062", ... ] 
  </code></pre>
  
  <p>How can this be attained? </p>