I am using jquery datatable for displaying data in table, When I export tabel info to PDF,Excel or CSV I need to exclude or hide some columns. 

```js
$(document).ready(function() {
var oTable = $('#example').DataTable( {
        dom: 'Blfrtip',
        buttons: [
       {
           extend: 'pdf',
           footer: true
       },
       {
           extend: 'csv',
           footer: false
       },
       {
           extend: 'excel',
           footer: false
       }         
    ]  
    } );

} );
```

```html
<link rel="stylesheet" href="https://cdn.datatables.net/buttons/1.1.0/css/buttons.dataTables.min.css" type="text/css"  />
<link rel="stylesheet" href="https://cdn.datatables.net/1.10.10/css/jquery.dataTables.min.css" type="text/css" />
<link rel="stylesheet" href="https://cdn.datatables.net/select/1.1.0/css/select.dataTables.min.css" type="text/css" />

<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script type="text/javascript" src="https://datatables.net/release-datatables/media/js/jquery.js"></script>
<script type="text/javascript" src="https://datatables.net/release-datatables/media/js/jquery.dataTables.js"></script>
<script type="text/javascript" scr="https://datatables.net/release-datatables/extensions/TableTools/js/dataTables.tableTools.js"></script>

<script src="https://cdn.datatables.net/buttons/1.1.0/js/dataTables.buttons.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jszip/2.5.0/jszip.min.js"></script>
<script src="https://cdn.rawgit.com/bpampuch/pdfmake/0.1.18/build/pdfmake.min.js"></script>
<script src="https://cdn.rawgit.com/bpampuch/pdfmake/0.1.18/build/vfs_fonts.js"></script>
<script src="https://cdn.datatables.net/buttons/1.1.0/js/buttons.html5.min.js"></script>

<script src="https://jquery-datatables-column-filter.googlecode.com/svn/trunk/media/js/jquery.dataTables.columnFilter.js" type="text/javascript"></script>

<table id="example" class="display" cellspacing="0" width="100%">
    <thead>
        <tr>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Age</th>
            <th>Start date</th>
            <th>Salary</th>
        </tr>
    </thead>

    <tfoot>
        <tr>
            <th>Name</th>
            <th>Position</th>
            <th>Office</th>
            <th>Age</th>
            <th>Start date</th>
            <th>Salary</th>
        </tr>
    </tfoot>

    <tbody>
        <tr>
            <td>Tiger Nixon</td>
            <td>System Architect</td>
            <td>Edinburgh</td>
            <td>61</td>
            <td>2011/04/25</td>
            <td>$320,800</td>
        </tr>
        <tr>
            <td>Garrett Winters</td>
            <td>Accountant</td>
            <td>Tokyo</td>
            <td>63</td>
            <td>2011/07/25</td>
            <td>$170,750</td>
        </tr>
        <tr>
            <td>Ashton Cox</td>
            <td>Junior Technical Author</td>
            <td>San Francisco</td>
            <td>66</td>
            <td>2009/01/12</td>
            <td>$86,000</td>
        </tr>
        <tr>
            <td>Cedric Kelly</td>
            <td>Senior Javascript Developer</td>
            <td>Edinburgh</td>
            <td>22</td>
            <td>2012/03/29</td>
            <td>$433,060</td>
        </tr>
        <tr>
            <td>Airi Satou</td>
            <td>Accountant</td>
            <td>Tokyo</td>
            <td>33</td>
            <td>2008/11/28</td>
            <td>$162,700</td>
        </tr>
        <tr>
            <td>Brielle Williamson</td>
            <td>Integration Specialist</td>
            <td>New York</td>
            <td>61</td>
            <td>2012/12/02</td>
            <td>$372,000</td>
        </tr>
        <tr>
            <td>Herrod Chandler</td>
            <td>Sales Assistant</td>
            <td>San Francisco</td>
            <td>59</td>
            <td>2012/08/06</td>
            <td>$137,500</td>
        </tr>
        <tr>
            <td>Rhona Davidson</td>
            <td>Integration Specialist</td>
            <td>Tokyo</td>
            <td>55</td>
            <td>2010/10/14</td>
            <td>$327,900</td>
        </tr>
        <tr>
            <td>Colleen Hurst</td>
            <td>Javascript Developer</td>
            <td>San Francisco</td>
            <td>39</td>
            <td>2009/09/15</td>
            <td>$205,500</td>
        </tr>
        <tr>
            <td>Sonya Frost</td>
            <td>Software Engineer</td>
            <td>Edinburgh</td>
            <td>23</td>
            <td>2008/12/13</td>
            <td>$103,600</td>
        </tr>
        <tr>
            <td>Jena Gaines</td>
            <td>Office Manager</td>
            <td>London</td>
            <td>30</td>
            <td>2008/12/19</td>
            <td>$90,560</td>
        </tr>
        <tr>
            <td>Quinn Flynn</td>
            <td>Support Lead</td>
            <td>Edinburgh</td>
            <td>22</td>
            <td>2013/03/03</td>
            <td>$342,000</td>
        </tr>
        <tr>
            <td>Charde Marshall</td>
            <td>Regional Director</td>
            <td>San Francisco</td>
            <td>36</td>
            <td>2008/10/16</td>
            <td>$470,600</td>
        </tr>
        <tr>
            <td>Haley Kennedy</td>
            <td>Senior Marketing Designer</td>
            <td>London</td>
            <td>43</td>
            <td>2012/12/18</td>
            <td>$313,500</td>
        </tr>
        <tr>
            <td>Tatyana Fitzpatrick</td>
            <td>Regional Director</td>
            <td>London</td>
            <td>19</td>
            <td>2010/03/17</td>
            <td>$385,750</td>
        </tr>
        <tr>
            <td>Michael Silva</td>
            <td>Marketing Designer</td>
            <td>London</td>
            <td>66</td>
            <td>2012/11/27</td>
            <td>$198,500</td>
        </tr>
        <tr>
            <td>Paul Byrd</td>
            <td>Chief Financial Officer (CFO)</td>
            <td>New York</td>
            <td>64</td>
            <td>2010/06/09</td>
            <td>$725,000</td>
        </tr>
        <tr>
            <td>Gloria Little</td>
            <td>Systems Administrator</td>
            <td>New York</td>
            <td>59</td>
            <td>2009/04/10</td>
            <td>$237,500</td>
        </tr>
        <tr>
            <td>Bradley Greer</td>
            <td>Software Engineer</td>
            <td>London</td>
            <td>41</td>
            <td>2012/10/13</td>
            <td>$132,000</td>
        </tr>
        <tr>
            <td>Dai Rios</td>
            <td>Personnel Lead</td>
            <td>Edinburgh</td>
            <td>35</td>
            <td>2012/09/26</td>
            <td>$217,500</td>
        </tr>
        <tr>
            <td>Jenette Caldwell</td>
            <td>Development Lead</td>
            <td>New York</td>
            <td>30</td>
            <td>2011/09/03</td>
            <td>$345,000</td>
        </tr>
        <tr>
            <td>Yuri Berry</td>
            <td>Chief Marketing Officer (CMO)</td>
            <td>New York</td>
            <td>40</td>
            <td>2009/06/25</td>
            <td>$675,000</td>
        </tr>
        <tr>
            <td>Caesar Vance</td>
            <td>Pre-Sales Support</td>
            <td>New York</td>
            <td>21</td>
            <td>2011/12/12</td>
            <td>$106,450</td>
        </tr>
        <tr>
            <td>Doris Wilder</td>
            <td>Sales Assistant</td>
            <td>Sidney</td>
            <td>23</td>
            <td>2010/09/20</td>
            <td>$85,600</td>
        </tr>
        <tr>
            <td>Angelica Ramos</td>
            <td>Chief Executive Officer (CEO)</td>
            <td>London</td>
            <td>47</td>
            <td>2009/10/09</td>
            <td>$1,200,000</td>
        </tr>
        <tr>
            <td>Gavin Joyce</td>
            <td>Developer</td>
            <td>Edinburgh</td>
            <td>42</td>
            <td>2010/12/22</td>
            <td>$92,575</td>
        </tr>
        <tr>
            <td>Jennifer Chang</td>
            <td>Regional Director</td>
            <td>Singapore</td>
            <td>28</td>
            <td>2010/11/14</td>
            <td>$357,650</td>
        </tr>
        <tr>
            <td>Brenden Wagner</td>
            <td>Software Engineer</td>
            <td>San Francisco</td>
            <td>28</td>
            <td>2011/06/07</td>
            <td>$206,850</td>
        </tr>
        <tr>
            <td>Fiona Green</td>
            <td>Chief Operating Officer (COO)</td>
            <td>San Francisco</td>
            <td>48</td>
            <td>2010/03/11</td>
            <td>$850,000</td>
        </tr>
        <tr>
            <td>Shou Itou</td>
            <td>Regional Marketing</td>
            <td>Tokyo</td>
            <td>20</td>
            <td>2011/08/14</td>
            <td>$163,000</td>
        </tr>
        <tr>
            <td>Michelle House</td>
            <td>Integration Specialist</td>
            <td>Sidney</td>
            <td>37</td>
            <td>2011/06/02</td>
            <td>$95,400</td>
        </tr>
        <tr>
            <td>Suki Burks</td>
            <td>Developer</td>
            <td>London</td>
            <td>53</td>
            <td>2009/10/22</td>
            <td>$114,500</td>
        </tr>
        <tr>
            <td>Prescott Bartlett</td>
            <td>Technical Author</td>
            <td>London</td>
            <td>27</td>
            <td>2011/05/07</td>
            <td>$145,000</td>
        </tr>
        <tr>
            <td>Gavin Cortez</td>
            <td>Team Leader</td>
            <td>San Francisco</td>
            <td>22</td>
            <td>2008/10/26</td>
            <td>$235,500</td>
        </tr>
        <tr>
            <td>Martena Mccray</td>
            <td>Post-Sales support</td>
            <td>Edinburgh</td>
            <td>46</td>
            <td>2011/03/09</td>
            <td>$324,050</td>
        </tr>
        <tr>
            <td>Unity Butler</td>
            <td>Marketing Designer</td>
            <td>San Francisco</td>
            <td>47</td>
            <td>2009/12/09</td>
            <td>$85,675</td>
        </tr>
        <tr>
            <td>Howard Hatfield</td>
            <td>Office Manager</td>
            <td>San Francisco</td>
            <td>51</td>
            <td>2008/12/16</td>
            <td>$164,500</td>
        </tr>
        <tr>
            <td>Hope Fuentes</td>
            <td>Secretary</td>
            <td>San Francisco</td>
            <td>41</td>
            <td>2010/02/12</td>
            <td>$109,850</td>
        </tr>
        <tr>
            <td>Vivian Harrell</td>
            <td>Financial Controller</td>
            <td>San Francisco</td>
            <td>62</td>
            <td>2009/02/14</td>
            <td>$452,500</td>
        </tr>
        <tr>
            <td>Timothy Mooney</td>
            <td>Office Manager</td>
            <td>London</td>
            <td>37</td>
            <td>2008/12/11</td>
            <td>$136,200</td>
        </tr>
        <tr>
            <td>Jackson Bradshaw</td>
            <td>Director</td>
            <td>New York</td>
            <td>65</td>
            <td>2008/09/26</td>
            <td>$645,750</td>
        </tr>
        <tr>
            <td>Olivia Liang</td>
            <td>Support Engineer</td>
            <td>Singapore</td>
            <td>64</td>
            <td>2011/02/03</td>
            <td>$234,500</td>
        </tr>
        <tr>
            <td>Bruno Nash</td>
            <td>Software Engineer</td>
            <td>London</td>
            <td>38</td>
            <td>2011/05/03</td>
            <td>$163,500</td>
        </tr>
        <tr>
            <td>Sakura Yamamoto</td>
            <td>Support Engineer</td>
            <td>Tokyo</td>
            <td>37</td>
            <td>2009/08/19</td>
            <td>$139,575</td>
        </tr>

    </tbody>
</table>
```

Can any one help me how do I exclude or hide some column like "AGE"...etc while exporting to PDF,Excel or CSV