title: How to query MongoDB from R?
body: <p>I want to get a MongoDB query from R.</p>
  
  <p>With the <code>mongo</code> shell, I would query with:</p>
  
  <pre><code>db.user.find({age:{$gt:21}})
  </code></pre>
  
  <p>However, In R-Mongo, I haven't found how to describe this query.</p>
  
  <p>Thanks</p>