XPath get only first Parent of nested HTML - xpath

Question

I am newbie in XPath. Can someone explain how to resolve this problem:
<table>
<tr>
<td>
<table>
<tr>
<td>
<table>
<tr>
<td>Label</td>
<td>value</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
</table>
I try to get <tr> which contains Label value, but it does not work for me,
Here is my code :
//td[contains(.,'Label')]/ancestor::tr[1]
Desired result:
<tr>
<td>Label</td>
<td>value</td>
</tr>
Can someone help me ?

Answer 1

This expression matches the tr that you want:
//tr[contains(td/text(), 'Label')]
Like yours, this starts by scanning all tr elements in the document, but this version uses just a single predicate. The td/text() limits the test to actual text nodes which are grandchildren of the row. If you just used td, then all of the td's descendant text nodes would be collected and concatenated, and the outer tr would match.
UPDATE: Also, for what it's worth, the reason your expression isn't working is that the ancestor axis returns elements in document order, not "outward" from the point of the context node. This is something I've run into myself, as it is somewhat unintuitive. To make your approach work, you would need to say
//td[contains(.,'Label')]/ancestor::tr[last()]
instead of
//td[contains(.,'Label')]/ancestor::tr[1]

Answer 2

I had the same issue, except that the text 'Label' was sometimes in a nested span, or even further nested in the td. For example:
<td><span>Label</span></td>
The previous answer only finds 'Label' if it is in a text element that is a direct child of the td. This issue is a bit harder because we need to search for a td that contains the text 'Label' in any of its children. Since the tds are nested, all tds qualify as having a descendant that contains the text 'Label'. So, the only way I found to overcome this is to add a check that makes sure that the td we select does not contain a td with the search text.
//td[contains(., 'Label') and not(.//td[contains(., 'Label')])]/ancestor::tr[1]
This says give me all of the tds that have a decedent text containing 'Label', but exclude all tds that contain a td that has a decedent text containing 'Label' (nesting ancestors). This returns the child most td that contains the text. Then you can go back to the tr that contains this td using ancestor.
Also, if you just want the lowest table that contains text use this:
//table[contains(., 'Label') and not(.//table[contains(., 'Label')])]
or you can select the tr directly:
//tr[contains(., 'Label') and not(.//tr[contains(., 'Label')])]
This seems like a common problem, but I didn't see a solution anywhere. So, I decided to post to this old unanswered question in hopes that it helps somebody.