XSL substring and indexOf

Question

I'm new to XSLT. I wonder if it is possible to select a substring of an item. I'm trying to parse an RSS feed. The description value has more text than what I want to show. I'd like to get a subtring of it based on the index of some substring. Basically, I want to show the result of a substring call passing indxOf('some_substring') and a length as parameters. Is this possible?

From comments:

I want to select the text of a string that is located after the occurrence of substring

Answer 1

It's not clear exactly what you want to do with the index of a substring [update: it is clearer now - thanks] but you may be able to use the function substring-after or substring-before:

substring-before('My name is Fred', 'Fred')

returns 'My name is '.

If you need more detailed control, the substring() function can take two or three arguments: string, starting-index, length. Omit length to get the whole rest of the string.

There is no index-of() function for strings in XPath (only for sequences, in XPath 2.0). You can use string-length(substring-before($string, $substring))+1 if you specifically need the position.

There is also contains($string, $substring). These are all documented here. In XPath 2.0 you can use regular expression matching.

(XSLT mostly uses XPath for selecting nodes and processing values, so this is actually more of an XPath question. I tagged it thus.)