title: Remove field found in any mongodb array
body: <p>I have a document looking like this:</p>
  
  <pre><code>{
  field: 'value',
  field2: 'value',
  scan: [
      [
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
      ],
      [
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
      ],
      [
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
          {
              dontDeleteMe: 'keepMe',
              arrayToDelete: [0,1,2]
          },
      ],
  
  ]
  
  }
  </code></pre>
  
  <p>We only want to delete any instance of the arrayToDelete that is in a dictionary nested in a list of lists in "scan".</p>
  
  <p>Currently, I've been using </p>
  
  <pre><code> update({}, {$unset: {"scans.0.0.arrayToDelete":1}}, {multi: true})
  </code></pre>
  
  <p>to delete the array. However, this only deletes the first <code>(0.0)</code> as you would imagine. </p>
  
  <p>Is it possible to iterate over the scan array and the nested array to delete "arrayToDelete", and keep all other fields?</p>
  
  <p>Thanks</p>