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5.44.1.The Element: Conditional Processing
5.44.2.Use if statement to test if an element as an attribute
5.44.3.Check two attributes
5.44.4.Nested if statement
5.44.5.if test="not(preceding-sibling::address[zip=$lastZip])"
5.44.6.if test="(position() mod 2) = 1"
5.44.7.select with if them else statement
5.44.8.xsl:if instruction enables conditional processing
5.44.9.Use if statement to check whether it is the last