title: MongoDB query $in with regex array of element
body: <p>Ok i am trying to implement a query, which is trying to perform regex search ( which contains an array list ) on a bunch of document</p>
  
  <p>Its hard for me to explain...so I am basically coming to direct point.</p>
  
  <p>There is query which works with regex array...</p>
  
  <pre><code>db.paper.find({"category": {$in: [ /xd/, /sd/, /ad/ ] }})
  </code></pre>
  
  <p>There is query which doesn't works with regex array...</p>
  
  <pre><code>db.paper.find({"category": {$in: [ "/xd/", "/sd/", "/ad/" ] }})
  </code></pre>
  
  <p>So basically what I want is remove "" sign from string array...so that i can perform below query..</p>
  
  <pre><code>var sea = [ "/xd/", "/sd/", "/ad/" ];
  db.paper.find({"category": {$in: sea }});
  </code></pre>