Namespace

These functions let you determine the namespace characteristics of a node.

• local-name(): Returns the name of the current node, minus the namespace prefix. Ie the element name (9/10 what we need). For example, /*[local-name()!='HEAD'] selects all elements excepted the HEAD elements.
• local-name(…): Returns the name of the first node in the specified node set, minus the namespace prefix.
• namespace-uri(): Returns the namespace URI from the current node.
• namespace-uri(…): Returns the namespace URI from the first node in the specified node-set.
• name(): Returns the expanded name (URI plus local name) of the current node.
• name(…): Returns the expanded name (URI plus local name) of the first node in the specified node-set.

Node-Set

Many XPath expressions select a set of nodes. In essence, they return a node-set.

The id(…) function returns the node with the specified ID (

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Positional

These functions return positionally based numeric values.

• last(): Returns the index of the last element. For example, /HEAD[last()] selects the last HEAD element.
• position(): Returns the index position. For example, /HEAD[position() ⇐ 5] selects the first five HEAD elements.
• count(…): Returns the count of elements. For example, /HEAD[count(HEAD)=0] selects all HEAD elements that have no subheads.

String

These functions operate on or return strings.

• concat(string, string, …): Concatenates the string values.
• starts-with(string1, string2): Returns true if string1 starts with string2.
• contains(string1, string2): Returns true if string1 contains string2.
• substring-before(string1, string2): Returns the start of string1 before string2 occurs in it.
• substring-after(string1, string2): Returns the remainder of string1 after string2 occurs in it.
• substring(string, idx): Returns the substring from the index position to the end, where the index of the first char = 1.
• substring(string, idx, len): Returns the substring of the specified length from the index position.
• string-length(): Returns the size of the context node's string-value; the context node is the currently selected node-the node that was selected by an XPath expression in which a function such as string-length() is applied.
• string-length(string): Returns the size of the specified string.
• normalize-space(): Returns the normalized string-value of the current node (no leading or trailing white space, and sequences of white space characters converted to a single space).
• normalize-space(string): Returns the normalized string-value of the specified string.
• translate(string1, string2, string3): Converts string1, replacing occurrences of characters in string2 with the corresponding character from string3.

Note - XPath defines three ways to get the text of an element:

• text(),
• string(object),
• and the string-value implied by an element name in an expression like this: /PROJECT[PERSON=“Fred”].

Boolean

These functions operate on or return Boolean values.

• not(…): Negates the specified Boolean value.
• true(): Returns true.
• false(): Returns false.
• lang(string): Returns true if the language of the context node (specified by xml:Lang attributes) is the same as (or a sub-language of) the specified language; for example, Lang(“en”) is true for <PARA_xml:Lang="en">…</PARA>

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Numeric

These functions operate on or return numeric values.

• sum(…): Returns the sum of the numeric value of each node in the specified node-set.
• floor(N): Returns the largest integer that is not greater than N.
• ceiling(N): Returns the smallest integer that is not less than N.
• round(N): Returns the integer that is closest to N.

Conversion

These functions convert one data type to another.

• string(…): Returns the string value of a number, Boolean, or node-set.
• boolean(…): Returns a Boolean value for a number, string, or node-set (a non-zero number, a non-empty node-set, and a non-empty string are all true).
• number(…): Returns the numeric value of a Boolean, string, or node-set (true is 1, false is 0, a string containing a number becomes that number, the string-value of a node-set is converted to a number).