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

I have the following Xpath expression:

//*[not(input)][ends-with(@*, 'Copyright')]

I expect it to provide me with all the elements - except input - with any attribute value that ends in "Copyright".

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

Expression is not legal Expression

But these expressions work without problems:

 //*[not(input)][starts-with(@*, 'Copyright')] //*[ends-with(@*, 'Copyright')]

Any ideas?

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4 answers

I have the following Xpath expression:

 //*[not(input)][ends-with(@*, 'Copyright')]

I expect it to give me all the elements - except the input - with any attribute value that ends with "Copyright".

There are several issues here :

  • ends-with() is a standard XPath 2.0 function, so it is likely that you are using the XPath 1.0 engine and it will correctly throw an error because it does not know about a function called ends-with() .

  • Even if you are working with an XPath 2.0 processor, the ends-with(@*, 'Copyright') expression will lead to an error in the general case, because the ends-with() function is defined to accept the maximum allowable single string ( xs:string? ) as both its operands, however, @* creates a sequence of more than one line in the case when an element has more than one attribute.

  • //*[not(input)] does not mean "select all elements that are not called input . Actual value:" Select all elements that do not have a child named "input".

Decision

  • Use this XPath 2.0 expression: //*[not(self::input)][@*[ends-with(.,'Copyright')]]

  • For XPath 1.0, use this expression:

....

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

Here is a short and complete check of the latest 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 conversion is applied to the following XML document:

 <html> <input/> <ax="Copyright not"/> <ay="This is a Copyright"/> </html>

required, the correct result is obtained :

 <ay="This is a Copyright"/>

In case the XML document is in the 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 to this XML document :

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

the desired, correct result is output:

 <a xmlns="http://www.w3.org/1999/xhtml" y="This is a Copyright"/>
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I do not know Selenium, but if //*[not(input)][starts-with(@*, 'Copyright')] successfully parsed and if the XPath 2.0 ends-with function is additionally supported, then I see no reason why //*[not(input)][ends-with(@*, 'Copyright')] 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 that do not have a child element, and //*[not(self::input)] selects any elements that are not input elements themselves. As for comparing [@*[ends-with(., 'Copyright')]] with what you have, my suggestion is true if there is any node attribute that ends with “Copyright” while your the test will work only if there is one attribute that ends with "Copyright", like end-with http://www.w3.org/TR/xquery-operators/#func-ends-with allow a sequence with one element as its first argument or an empty sequence, but not a few elements.

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Most likely, the explanation is that you are using XPath 1.0 processors. The end-with () function requires XPath 2.0 support.

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

There may be a slight correction with string-length(.)

Now it might work.

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