XML & XSL - xsl:for-each

Applies a template repeatedly to a set of nodes. Effectively applies whatever commands (template specifications) contained with the foreach loop as a method operating on the collection elements looped through by the foreach loop.

Syntax

<xsl:for-each order-by="sort-criteria-list" select="pattern">

Attributes

order-by - sort criteria in a semicolon-separated list. When the first sort results in two equal items, the second sort criterion is checked, and so on. The first non-white-space character in each sort criterion indicates whether the sort is ascending (optional +) or descending (-). The sort criterion is expressed as an XSL pattern, relative to the pattern described in the select attribute. Note that the order-by parameter has been deprecated in favor of the xsl:sort element.
select - XSL pattern query evaluated the current context to determine the set of nodes to iterate over. The default value "node()" indicates selection of all children of the current node.

Parent Elements

Child Elements

Purpose

xsl:for-each iterates or loops into a collection. Note that the collection objects within the loop can be looped with another xsl:for-loop.

The example below shows iteration through a loop contained within a loop within a loop. The first foreach loop iterates through countries, the second through states within countries and the third within cities within states. Note how each successive loop does not have to parse for what its enwrapping loop parse for. Each loop provides each enclosed loop with its iterative object. In other words when we parse for cities we parse for cities/city within states/state and not world/countries/country/states/state/cities/city.

Cities of the World

XML Data Tree Structure

Click here to see the XML structure of this example.

XML & XSL in Action

Click here to see the XSL formatted display of this example.

The XSL Style Sheet

<?xml version="1.0"?>

<HTML xmlns:xsl="http://www.w3.org/TR/WD-xsl">
<BODY STYLE="font-family:Arial, helvetica, sans-serif; font-size:12pt; background-color:#EEEEEE">

<H2>Cities</H2>

<UL>
	<xsl:for-each select="world/countries/country">
		<LI><FONT COLOR="red"><xsl:value-of select="name"/></FONT></LI>
		<UL>
			<xsl:for-each select="states/state">
				<LI><FONT COLOR="green"><xsl:value-of select="name"/></FONT></LI>
				<UL>
					<xsl:for-each select="cities/city">
						<LI><FONT COLOR="blue"><xsl:value-of select="name"/></FONT> is <xsl:value-of select="type"/></LI>
					</xsl:for-each>
				</UL>
			</xsl:for-each>
		</UL>
	</xsl:for-each>
</UL>

</BODY>
</HTML>

HTML Equivalent

<HTML>
<BODY>
<H2>Cities</H2>
<UL>
	<LI><FONT COLOR="red">Canada</FONT></LI>
	<UL>
		<LI><FONT COLOR="green">Quebec</FONT></LI> 
		<UL>
			<LI><FONT COLOR="blue">Montreal is French</FONT></LI>
		</UL>
		<LI><FONT COLOR="green">British Columbia</FONT></LI> 
		<UL>
			<LI><FONT COLOR="blue">Vancouver is Nice</FONT></LI> 
		</UL>
	</UL>
	<LI><FONT COLOR="red">United States</FONT></LI> 
	<UL>
		<LI><FONT COLOR="green">New York</FONT></LI> 
		<UL>
			<LI><FONT COLOR="blue">New York City is Commercial</FONT></LI> 
			<LI><FONT COLOR="blue">Buffalo is Big Snow Balls</FONT></LI> 
		</UL>
		<LI><FONT COLOR="green">California</FONT></LI> 
		<UL>
			<LI><FONT COLOR="blue">San Francisco is Silicon Valley</FONT></LI> 
			<LI><FONT COLOR="blue">Los Angeles is Polluted</FONT></LI>
			<LI><FONT COLOR="blue">San Diego is Sunny</FONT></LI>
		</UL>
	</UL>
</UL>
</BODY>
</HTML>