XSLT Filtering based on nodes and attributes - xslt

Question

I'm new on XSLT and have a requirement to use XSLT to select values from an XML file of this form :
<?xml version="1.0" encoding="utf-8"?>
<deviceInstallation>
<order>
<orderID>296</orderID>
<orderPosID>1</orderPosID>
<action rvcd="2">unInstall</action>
</order>
<deviceInfo>
<actionInfo rvcd="1">Software Install</actionInfo>
<device>
<deviceID>1436</deviceID>
</device>
</deviceInfo>
<deviceInfo>
<actionInfo rvcd="2">Software Uninstall</actionInfo>
<device>
<deviceID>4112</deviceID>
</device>
</deviceInfo>
</deviceInstallation>
I need to filter the elements deviceinfo based on the attribute rvcd = 2 because this is what is defined on the same attribute of child element action of the order element.
I tried to write and xslt and used a var to get the value to filter but don't know how to use it :
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsl:output method="text" />
<xsl:variable name="separator" select="';'" />
<xsl:variable name="newline" select="'
'" />
<xsl:variable name="actionFilter" select="/deviceInstallation/order/action[]/#rvcd" />
<xsl:template match="/">
<xsl:text>orderID;DeviceID</xsl:text>
<xsl:value-of select="$newline" />
<xsl:for-each select="/deviceInstallation">
<!--OrderID-->
<xsl:value-of select="/deviceInstallation/order/orderID"/>
<xsl:value-of select="$separator"/>
<!--DeviceID-->
<xsl:value-of select="/deviceInstallation/deviceInfo/device/deviceID"/> <!-- here want to filter on rvcd-->
<xsl:value-of select="$separator"/>
<xsl:value-of select="$newline" />
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Any help appreciated

Answer 1

IIUC, you want to do:
XSLT 1.0
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" />
<xsl:template match="/deviceInstallation">
<xsl:variable name="orderID" select="order/orderID" />
<xsl:variable name="actionFilter" select="order/action/#rvcd" />
<xsl:text>orderID;DeviceID
</xsl:text>
<xsl:for-each select="deviceInfo[actionInfo/#rvcd=$actionFilter]">
<xsl:value-of select="$orderID" />
<xsl:text>;</xsl:text>
<xsl:value-of select="device/deviceID" />
<xsl:text>
</xsl:text>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
or perhaps a bit more elegantly:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" />
<xsl:key name="dev" match="deviceInfo" use="actionInfo/#rvcd" />
<xsl:template match="/deviceInstallation">
<xsl:variable name="orderID" select="order/orderID" />
<xsl:text>orderID;DeviceID
</xsl:text>
<xsl:for-each select="key('dev', order/action/#rvcd)">
<xsl:value-of select="$orderID" />
<xsl:text>;</xsl:text>
<xsl:value-of select="device/deviceID" />
<xsl:text>
</xsl:text>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>