I don't see the necessity for reversing the content. True, "greedy" matching
(implying backup) may not be the fastest way in some situations; as an
alternative there is "reluctant" matching (e.g. '.*?').
But if the YYY is a literal string (not a pattern) substring-before is
suffcient.
<out1>
<xsl:variable name="bef" select="substring-before(.,'YYY')"/>
<xsl:value-of select="substring($bef,string-length($bef)-400+1,400)"/>
</out1>
If there's the possibility that there aren't 400 characters before YYY,
add a choice.
Here is the solution with pattern matching:
<out2>
<xsl:variable name="bef" select="."/>
<xsl:value-of select="replace($bef,'^.*?(.{400})YYY.*$', '$1')"/>
</out2>
Here, using '.{1,400}' would be necessary to handle "short" cases.
-W
On 13 June 2010 10:11, Alex Muir <alex(_dot_)g(_dot_)muir(_at_)gmail(_dot_)com>
wrote:
Hi,
I need to select 400 characters before a string such as YYY in a
larger text document.
I've in the past reversed the content to then find the 400 characters
before YYY using regex effectively however I'm wondering if there is a
better perhaps simpler way to do this in xslt?
Thanks
--
Alex
An informal recording with one mic under a tree leads to some pretty
sweet acoustic sounds.
https://sites.google.com/site/greigconteh/albums/diabarte-and-sons
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