xslforeach

The xsl:for-each element is a fundamental instruction in XSLT (Extensible Stylesheet Language Transformations). It is used to iterate over a selected set of nodes in an XML document and apply a template to each node in that set. The xsl:for-each element is analogous to a loop in traditional programming languages.

The selection of nodes to be iterated over is defined by an XPath expression in the select attribute of the xsl:for-each element. For each node that matches the XPath expression, the content within the xsl:for-each element, which typically consists of other XSLT instructions and literal XML, is processed.

Within the scope of an xsl:for-each loop, the current node changes with each iteration. This allows for relative XPath expressions to target specific data within the current node being processed. For example, to output the text content of each 'item' element within a parent element, one might use xsl:for-each select="item" and then inside, an xsl:value-of select="." to output the text of the current item.

The xsl:for-each instruction processes nodes in the order they appear in the source XML document, unless an xsl:sort element is included within the xsl:for-each to explicitly define the sorting order. This sorting capability is crucial for presenting data in a structured and user-friendly manner.

It's important to note that xsl:for-each cannot be used in conjunction with xsl:apply-templates when selecting the same set of nodes, as this can lead to unexpected results and infinite loops. The choice between xsl:for-each and xsl:apply-templates often depends on the desired output structure and the complexity of the transformation. xsl:for-each is generally favored for straightforward, sequential processing of a node set.