Xpath error with not() and ends-with()

java xpath selenium-webdriver

22,061

Solution 1

I have the following Xpath expression:
//*[not(input)][ends-with(@*, 'Copyright')]
I expect it to give me all elements - except input - with any attribute value which ends with "Copyright".

There are a few issues here:

ends-with() is a standard XPath 2.0 function only, so the chances are you are using an XPath 1.0 engine and it correctly raises an error because it doesn't know about a function called ends-with().
Even if you are working with an XPath 2.0 processor, the expression ends-with(@*, 'Copyright') results in error in the general case, because the ends-with() function is defined to accept atmost a single string (xs:string?) as both of its operands -- however @* produces a sequence of more than one string in the case when the element has more than one attribute.
//*[not(input)] doesn't mean "select all elements that are not named input. The real meaning is: "Select all elements that dont have a child element named "input".

Solution:

Use this XPath 2.0 expression: //*[not(self::input)][@*[ends-with(.,'Copyright')]]
In the case of XPath 1.0 use this expression:

....

  //*[not(self::input)]
        [@*[substring(., string-length() -8) = 'Copyright']]

Here is a short and complete verification of the last XPath expression, using XSLT:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/*">
     <xsl:copy-of select=
     "//*[not(self::input)]
           [@*[substring(., string-length() -8)
              = 'Copyright'
              ]
          ]"/>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the following XML document:

<html>
 <input/>
 <a x="Copyright not"/>
 <a y="This is a Copyright"/>
</html>

the wanted, correct result is produced:

<a y="This is a Copyright"/>

In the case of the XML document being in a default namespace:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:x="http://www.w3.org/1999/xhtml"
 >
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/*">
     <xsl:copy-of select=
     "//*[not(self::x:input)]
           [@*[substring(., string-length() -8)
              = 'Copyright'
              ]
          ]"/>
 </xsl:template>
</xsl:stylesheet>

when applied on this XML document:

<html xmlns="http://www.w3.org/1999/xhtml">
 <input z="This is a Copyright"/>
 <a x="Copyright not"/>
 <a y="This is a Copyright"/>
</html>

the wanted, correct result is produced:

<a xmlns="http://www.w3.org/1999/xhtml" y="This is a Copyright"/>

Solution 2

I don't know Selenium but if //*[not(input)][starts-with(@*, 'Copyright')] is parsed successfully and if additionally the XPath 2.0 function ends-with is supported then I don't see any reason why //*[not(input)][ends-with(@*, 'Copyright')] is not accepted as a legal expression. Your verbal description however sounds as if you want //*[not(self::input)][@*[ends-with(., 'Copyright')]].

//*[not(input)] selects any elements not having any input child element while //*[not(self::input)] selects any elements not being themselves input elements. As for comparing [@*[ends-with(., 'Copyright')]] with what you have, my suggestion is true as long as there is any attribute node which ends with 'Copyright' while your test would only work if there is a single attribute which ends with 'Copyright', as ends-with http://www.w3.org/TR/xquery-operators/#func-ends-with allow a sequence with a single item as its first argument or an empty sequence but not several items.

22,061

Author by

Alp

I am passionate for all topics related to web development. In particular i enjoy writing code in Python and JavaScript. I love opportunities to learn about state-of-the-art techniques, developing useful features with pleasant UX and establishing stable build and deploy chains.

Updated on July 09, 2022

Comments

Alp almost 2 years
I have the following Xpath expression:
```
//*[not(input)][ends-with(@*, 'Copyright')]
```
I expect it to give me all elements - except input - with any attribute value which ends with "Copyright".

I execute it in the Selenium 2 Java API with webDriver.findElements(By.xpath(expression)) and get the following error:

The expression is not a legal expression

But these expressions work without trouble:
```
//*[not(input)][starts-with(@*, 'Copyright')]
//*[ends-with(@*, 'Copyright')]
```
Any ideas?
Alp about 13 years

Got the same error for //*[not(self::input)][@*[ends-with(., 'Copyright')]].
Martin Honnen about 13 years

Are you sure Selenium supports an XPath 2.0 function like ends-with?
Martin Honnen about 13 years

As far as I understand XPath the expressions are fine. However I don't know Selenium so I don't know why it complains and can't help with that. Hopefully someone else comes along and can tell you what is wrong.
Alp about 13 years

Anyway thanks for your help. I think i have to ask this in the Selenium usergroup.
Alp about 13 years

Thank you, i will check this later.
Dimitre Novatchev about 13 years

@Martin Honnen: [Re: I don't see any reason why //*[not(input)][ends-with(@*, 'Copyright')] is not accepted as a legal expression] See my answer for explanation why this should produce (as it does) a runtime error.
Alp about 13 years

Sadly not working too: The expression is not a legal expression: xpath=//*[not(self::input)][@*[substring(., string-length()-8) = 'Copyright')]]
Dimitre Novatchev about 13 years

@Alp: Seems you are not working with a compliant XPath processor -- if so, your question will be better adressed in a more specific tag, not in the "xpath" tag, which assumes that the question is an XPath question.
Dimitre Novatchev about 13 years

@Alp: I edited my answer and it now includes a complete XSLT-based verification of the second XPath expression. You may just run this verification yourself and see that the wanted result is produced.
Adam almost 13 years

Selenium uses the browser's XPath engine so it is likely a complete implementation. I've had issues with frames or multiple windows and Selenium focus for XPaths. Are you using any of those features?
Dimitre Novatchev almost 13 years

Please, note, @Adam, that "complete" isn't a synonym for "compliant" or "correct". There is a W3C test suite -- run Selenium on it.
Adam almost 13 years

@Dimitre - I believe we've had this discussion in other comment threads. :)
yegor256 almost 11 years

Yes, starts-with is also from XPath 2.0
Michael Kay almost 11 years

No, starts-with was available in 1.0. ends-with was new in 2.0.