title: How to chunk an array in Ruby
body: <p>In Ruby 1.8.6, I have an array of, say, 100,000 user ids, each of which is an int.  I want to perform a block of code on these user ids but I want to do it in chunks.  For example, I want to process them 100 at a time.  How can I easily achieve this as simply as possible?</p>
  
  <p>I could do something like the following, but probably there's an easier way:</p>
  
  <pre><code>a = Array.new
  userids.each { |userid|
    a &lt;&lt; userid
    if a.length == 100
      # Process chunk
      a = Array.new
    end
  }
  unless a.empty?
    # Process chunk
  end
  </code></pre>