Hi gurus, I am a beginner on XSLT. Appreciate if you can shed some light regarding the behavior of for-each & if dealing with a document array which contains another document array. See below

Example Doc Structure:
-EventMatters[1]: XML Document Array
   /EventMattersResult[1] : a XML document Array inside EventMatters
   /EventMattersResult[2]
-EventMatters[2]
   /EventMattersResult[1]

The code :
1) <xsl:for-each select="EventMatters/EventMattersResult">
2) <xsl:if test="EventMatters/EventMattersResult/Result = $VARIABLE">

My Question :
1) Hows does the xslt for-each works in this case? Does it 1st loop EventMatters, then loop on EvenMattersResult and so on? or does it only takes the 1st index of EventMatters and only loop the EventMattersResult?

2) Does the same doc rule for-each applies to the if condition?

Thank you

xsl:for-each does not loop, it applies its instructions to each node in the selected set. I'd find it easier to answer if you showed some real XML.

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Joe (Microsoft MVP - XML)

You're inventing your own terminology "document array" to explain your data model - it would make for better communication if your learnt the standard vocabulary. XML does not have arrays.

The code

<xsl:for-each select="EventMatters/EventMattersResult">
   ...
</xsl:for-each>

is equivalent to a nested loop:

<xsl:for-each select="EventMatters">
  <xsl:for-each select="EventMattersResult">

The expression EventMatters/EventMattersResult returns a node-set (or in 2.0, a node sequence) containing all the EventMattersResult children of all the EventMatters children of the context node.

In the expression

<xsl:if test="EventMatters/EventMattersResult/Result = $VARIABLE">

once again EventMatters/EventMattersResult/Result selects a node-set. The semantics of "=" in XPath, when one of the operands is a node-set, are that the operator returns true if any item on the lhs is equal to any item on the rhs; so (assuming that $VARIABLE holds a string) you are testing whether any of the nodes in the node-set is equal to the variable.



Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Thank you very much joe & michael for your feedback.
I do have one more question assuming the following code :-

<xsl:variable name="LocnCode" select="substring(EventMatters/EventMatterResults/Order,1,2)"/>

I understand that this code performs a substring of variable Order and assigns it to variable name = LocnCode, however I am confused that Order is part of EventMatter/EventMatterResults which is a node set, so does this means that LocnCode will contain data of substring in each node in EventMatter/EventMatterResults?

In XPath 2.0 it is an error to pass a node-set containing more than one node as an argument to functions like substring().

In XPath 1.0 the node-set is converted to a string by taking the string value of the first node in the node-set and ignoring the other nodes. This is probably not what you want, which is why it has been outlawed in 2.0 (unless you run in backwards compability mode).

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

Thank you very much Michael, your info really help me. I undertstand the concept now. :D