title: How to prevent MongoDB from returning the object ID when finding a document?
body: <p>I've the following document in MongoDB...</p>
  
  <pre><code>{
    "_id" : ObjectId("531221cd960100960116b992"),
    "username : "joe",
    "address" : [
      {
        "zip" : "8000",
        "city" : "Zurich"
      },
      {
        "zip" : "6900",
        "city" : "Lugano"
      }
    ]
  }
  </code></pre>
  
  <p>... and to retrieve the second address I use the following statement:</p>
  
  <pre><code>db.users.find({ _id: ObjectId("531221cd960100960116b992") }, { addresses: { $slice: [0, 1] } } )
  </code></pre>
  
  <p>This works except it also returns the object id:</p>
  
  <pre><code>{ "addresses" : [ { "zip" : "6900", "city" : "Lugano" } ], "_id" : ObjectId("531221cd960100960116b992") }
  </code></pre>
  
  <p>How do I prevent MongoDB from returning the object id? I know I should provide a projection like <code>_id : 0</code>... but where should I put it in the expression above? I did a number of tries... but without success.</p>
  
  <p>Thanks.</p>