xpath/xquery to eleminate certain nodes

[Christian Schlaefcke]

Hi,

I am fighting with a xpath/xquery expression to select the whole xml
document except of certain nodes that I want to remove. The general
structure of the document should be preserved.

With my approaches I either select too much or too less and my research @
google & co. did not bring me any further :-(

The document structure is a bit tricky (arbitrarily nested categories) -
imagine the following document:
<sites>
  <site>
    <categories>
      <category name="root">
        <categories>
          <category name="category_1">
            <some>
              <further>
                <nested>
                  <info info_id="1">Important Information</info>
                </nested>
              </further>
            </some>
          </category>
          <category name="category_2">
            <some>
              <further>
                <nested>
                  <info info_id="2">Less Important Information</info>
                </nested>
              </further>
            </some>
          </category>
        </categories>
      </category>
      <category name="hidden">
        <categories>
          <category name="dont_need_it">
            <some>
              <further>
                <nested>
                  <info info_id="3">Unimportant Information</info>
                </nested>
              </further>
            </some>
          </category>
          <category name="dont_need_it_too">
            <some>
              <further>
                <nested>
                  <info info_id="4">Even More Unimportant Information</info>
                </nested>
              </further>
            </some>
          </category>
        </categories>
      </category>
    </categories>
  </site>
</sites>

What I want would be:
<sites>
  <site>
    <categories>
      <category name="root">
        <categories>
          <category name="category_1">
            <some>
              <further>
                <nested>
                  <info info_id="1">Important Information</info>
                </nested>
              </further>
            </some>
          </category>
        </categories>
      </category>
    </categories>
  </site>
</sites>

I tried several approaches like:
/site/sites//categories/category[@name = 'category_1']
or
/site/sites//categories/category[@name != 'hidden']
or
/site/sites//categories/category/some/further/nested/info[@info_id = '1']

But all I get is something like this:
<category name="category_1">
  <some>
    <further>
      <nested>
        <info info_id="1">Important Information</info>
      </nested>
    </further>
  </some>
</category>

What is missing to preserve the parent xml data?

Any hint that will point me to the right direction would be very appreciated!

Thank & Regards,

Christian