Appendix C. XPath Functions and Examples

The following tables contain brief examples, definitions, and text references to the XPath functions available. No text references are available because functions weren't discussed in the book. Not all functions are discussed in this table. Please refer to any of the excellent texts , such as XSLT A Programmer's Reference by Michael Kay, Second Edition,WROX Press, on this subject for further information.

XPath Functions	Example	Description
ARITHMETIC FUNCTIONS
ceiling	ceiling(14 div 3) = 5	Returns the smallest integer greater than or equal to the numeric value of the argument.
floor	floor(4.5) = 4	Returns the largest integer less than or equal to the numeric value of the argument.
round	round(9.6) = 10	Returns the closest integer to the numeric value of the argument.
BOOLEAN FUNCTIONS
false	xsl:if test=false()	Returns the Boolean false.
true	xsl:if test=true()	Returns the Boolean true.
not	not(false()) returns true	Returns the Boolean negation of its argument.
CONTEXT INFORMATION FUNCTIONS
current	If @LastName is the context node current() returns a one-node node set of @LastName's value.	Returns the context node.
last	<xsl:if test="position() != last()" </xsl:if>	Returns the number of the last node in the node set.
position	<xsl:if test="position() < 3" </xsl:if>	Returns the number of the thecurrent node in the node set.
DATA CONVERSION FUNCTIONS
boolean	Boolean(0) returns false	Converts the argument to a Boolean value.
format-number	format-number (value, format) produces a formatted string.	Converts numbers to strings for display. The format is controlled by decimal-format.
number	number('-32.4') returns -32.4 as a number.	Converts its argument to a number.
string	string(-32.4) returns '-32.4'.	Converts its argument to a string.
PROCESSOR INFORMATION FUNCTIONS
element-available	<xsl:element-available ('xsl:comment') returns true.	Tests whether a specific controlled instruction or extension is available.
function-available	<xsl:function-available ('string') returns true.	Tests whether a specific XSLT function or extension is available.
RETRIEVING NAMES AND IDS FUNCTIONS
name	<xsl:if test="not(@LastName)"> </xsl:if	Returns a Qname representing a node name.
STRING FUNCTIONS
concat	<xsl:value-of select="concat('address', 'city', 'state', 'zip')" />	Joins two or more arguments as strings.
contains	contains('Winston', 'ton') returns true.	Tests whether a string is contained within another string.
string-length	string-length('four score') returns 10.	Returns the character count in a string.
substring	substring('four score', 2, 3) returns 'our'.	Returns a portion of a string based on position attributes starting at 1.
SUMMARY FUNCTIONS
count	if test="count('resume/address [zip]') != 0"	Returns the number of nodes in a node set.
sum	the node <tri a='10' b='20' c='30' Returns 60 with the expression sum(@*)	Calculates the total of a set of numbers in a node set.