XPath：在节点集上使用字符串函数？

Question

I am wondering if it is possible to use string functions on a node-set - specifically the 'substring()' function in XPath 1.0.

The page I am scraping details from has a node-set of 5 URLs that are returned with the following XPath location path:

//div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href

Unfortunately, the URLs are in '//www.example.com' format - I need these in 'www.example.com' format (without the leading slashes). I have tried:

substring(//div[@class='example example-1']/a[not(contains(div,'Sold'))]/@href, 3)

However, this only returns 1 result. I need all 5 returned without the leading slashes. My guess is that you cannot use this kind of string function on a node-set, but hoping someone can shed light on this and help me achieve my desired result, please?

If there are alternative methods of achieving the same result, then I'm all ears too.

Thanks

Answer 1

There is no way to process each item of an arbitrary list or node-set with a function in pure XPath 1 so you will need to drop down to the host language you use XPath with to process the different nodes separately and call the substring function on each item from the host language (eg XSLT <xsl:for-each select="/div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href"><xsl:value-of select="substring(., 3)"/></xsl:for-each> ).

In XPath 2 and later you can use either use the function call in or as the last step eg /div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href/substring(., 3) or use a for .. return expression eg for $href in /div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href return substring($href, 3) but there is no such option in pure XPath 1.

Of course if you know you have five items, then depending on the way you use XPath (the host language or the tool) you might be able to use five path expressions eg substring((/div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href)[1], 3) , substring((/div[@class='titles cf']/a[not(contains(div,'Sold'))]/@href)[2], 3) etc.