Online XPath tester

Returns the position of the current context node

W3C Documentation reference: Node-Set-Functions

Returns the number of nodes in the node-set
Arguments and return type:

Type	Description
node-set	Node-set to count nodes in

Examples:

Expression	Result
count(//b:book)	5
count(//person[@id>5])	17

W3C Documentation reference: Node-Set-Functions

Returns the element specified by it's unique id, requires DTD

W3C Documentation reference: Node-Set-Functions

Returns the local-name for the first node in the node-set
Arguments and return type:

Type	Description
node-set	Extract first node and return its local name

Examples:

Expression	Result
local-name(//b:books)	b:book
local-name(//b:book)	b:title

W3C Documentation reference: Node-Set-Functions

Returns the local-name for the context node

W3C Documentation reference: Node-Set-Functions

Returns the namespace-uri for the first node in the node-set
Arguments and return type:

Type	Description
node-set	Extract first node and return the namespace URI

Examples:

Expression	Result
namespace-uri(//b:book)	http://www.book.com

W3C Documentation reference: Node-Set-Functions

Returns the namespace-uri for the context node

W3C Documentation reference: Node-Set-Functions

Returns the name for the first node in the node-set
Arguments and return type:

Type	Description
node-set	Extract first node and return QName

Examples:

Expression	Result
name(//b:books/*)	b:book
name(//b:book/*)	b:title

W3C Documentation reference: Node-Set-Functions

Returns the name for the context node
Examples:

Expression	Result
current context node	Extract first node and return QName

W3C Documentation reference: Node-Set-Functions

The boolean function converts its argument to a boolean as follows:

• a number is true if and only if it is neither positive or negative zero nor NaN
• a node-set is true if and only if it is non-empty
• a string is true if and only if its length is non-zero
• an object of a type other than the four basic types is converted to a boolean in a way that is dependent on that type

Arguments and return type:

Type	Description
object	The object to convert to a boolean

Examples:

Expression	Result
boolean("Release11")	true
boolean("")	false

W3C Documentation reference: Boolean-Functions

The not function returns true if its argument is false, and false otherwise.

W3C Documentation reference: Boolean-Functions

The true function returns true.

W3C Documentation reference: Boolean-Functions

The true function returns false.

W3C Documentation reference: Boolean-Functions

The lang function returns true or false depending on whether the language of the context node as specified by xml:lang attributes is the same as or is a sublanguage of the language specified by the argument string. The language of the context node is determined by the value of the xml:lang attribute on the context node, or, if the context node has no xml:lang attribute, by the value of the xml:lang attribute on the nearest ancestor of the context node that has an xml:lang attribute. If there is no such attribute, then lang returns false. If there is such an attribute, then lang returns true if the attribute value is equal to the argument ignoring case, or if there is some suffix starting with - such that the attribute value is equal to the argument ignoring that suffix of the attribute value and ignoring case.
Arguments and return type:

Type	Description
string	Language that will be looked for in context node

Examples: Look W3C documentation

W3C Documentation reference: Boolean-Functions

Returns the name of a node, as an xs:string that is either the zero-length string, or has the lexical form of an xs:QName.
If the argument is omitted, it defaults to the context item (.). The behavior of the function if the argument is omitted is exactly the same as if the context item had been passed as the argument.
The following errors may be raised: if the context item is undefined [err:XPDY0002]XP; if the context item is not a node [err:XPTY0004]XP.
If the argument is supplied and is the empty sequence, the function returns the zero-length string.
If the target node has no name (that is, if it is a document node, a comment, a text node, or a namespace binding having no name), the function returns the zero-length string.
Otherwise, the value returned is fn:string(fn:node-name($arg)).

Arguments:

Type	Description
node?	Node to display name.

Return type: xs:string

Examples:

Query	Result
name(/l:library)	l:library

W3C Documentation reference

Returns the local part of the name of $arg as an xs:string that will either be the zero-length string or will have the lexical form of an xs:NCName.
If the argument is omitted, it defaults to the context item (.). The behavior of the function if the argument is omitted is exactly the same as if the context item had been passed as the argument.
The following errors may be raised: if the context item is undefined [err:XPDY0002]XP; if the context item is not a node [err:XPTY0004]XP.
If the argument is supplied and is the empty sequence, the function returns the zero-length string.
If the target node has no name (that is, if it is a document node, a comment, or a text node), the function returns the zero-length string.
Otherwise, the value returned will be the local part of the expanded-QName of the target node (as determined by the dm:node-name accessor in Section 5.11 node-name Accessor). This will be an xs:string whose lexical form is an xs:NCName.

Arguments:

Type	Description
node?	Node to display local-name.

Return type: xs:string

Examples:

Query	Result
name(/l:library)	library

W3C Documentation reference

Returns an xs:boolean indicating whether the argument node is "nilled". If the argument is not an element node, returns the empty sequence. If the argument is the empty sequence, returns the empty sequence.

Arguments:

Type	Description
node?	Node to test.

Return type: xs:boolean?

Examples:

Query	Result
nilled(/l:library)	false

W3C Documentation reference

Returns the value of the base-uri URI property for $arg as defined by the accessor function dm:base-uri() for that kind of node in Section 5.2 base-uri AccessorDM. If $arg is not specified, the behavior is identical to calling the function with the context item (.) as argument. The following errors may be raised: if the context item is undefined [err:XPDY0002]XP; if the context item is not a node [err:XPTY0004]XP.
If $arg is the empty sequence, the empty sequence is returned.
Document, element and processing-instruction nodes have a base-uri property which may be empty. The base-uri property of all other node types is the empty sequence. The value of the base-uri property is returned if it exists and is not empty. Otherwise, if the node has a parent, the value of dm:base-uri() applied to its parent is returned, recursively. If the node does not have a parent, or if the recursive ascent up the ancestor chain encounters a node whose base-uri property is empty and it does not have a parent, the empty sequence is returned.

Arguments:

Type	Description
node?	Node to find base URI of.

Return type: xs:anyURI?

Examples:

Query	Result
base-uri(/l:library/l:libraryName)	<empty sequence>

W3C Documentation reference

Returns the value of the document-uri property for $arg as defined by the dm:document-uri accessor function defined in Section 6.1.2 AccessorsDM.
If $arg is the empty sequence, the empty sequence is returned.
Returns the empty sequence if the node is not a document node. Otherwise, returns the value of the dm:document-uri accessor of the document node.
In the case of a document node $D returned by the fn:doc function, or a document node at the root of a tree containing a node returned by the fn:collection function, it will always be true that either fn:document-uri($D) returns the empty sequence, or that the following expression is true: fn:doc(fn:document-uri($D)) is $D. It is implementation-defined whether this guarantee also holds for document nodes obtained by other means, for example a document node passed as the initial context node of a query or transformation.

Arguments:

Type	Description
node?	Node which document-uri value needs to be returned.

Return type: xs:anyURI?

Examples:

Query	Result
document-uri(/l:library/l:libraryName)	<empty sequence>

W3C Documentation reference

Returns the position of the last node in the context list

W3C Documentation reference: Node-Set-Functions

The boolean function converts its argument to a boolean as follows:

• a number is true if and only if it is neither positive or negative zero nor NaN
• a node-set is true if and only if it is non-empty
• a string is true if and only if its length is non-zero
• an object of a type other than the four basic types is converted to a boolean in a way that is dependent on that type

Arguments and return type:

Type	Description
object	The object to convert to a boolean

Examples:

Expression	Result
boolean("Release11")	true
boolean("")	false

W3C Documentation reference: Boolean-Functions

Returns the value of $arg represented as a xs:string. If no argument is supplied, the context item (.) is used as the default argument. The behavior of the function if the argument is omitted is exactly the same as if the context item had been passed as the argument.
If the context item is undefined, error [err:XPDY0002]XP is raised.
If $arg is the empty sequence, the zero-length string is returned.
If $arg is a node, the function returns the string-value of the node, as obtained using the dm:string-value accessor defined in the Section 5.13 string-value AccessorDM.
If $arg is an atomic value, then the function returns the same string as is returned by the expression " $arg cast as xs:string " (see 17 Casting).
Arguments and return type:

Type	Description
string	The object to convert to a string

Examples:

Expression	Result
string((1<0))	false
string(.11)	0.11

W3C Documentation reference

Returns the value indicated by $arg or, if $arg is not specified, the context item after atomization, converted to an xs:double
Calling the zero-argument version of the function is defined to give the same result as calling the single-argument version with the context item (.). That is, fn:number() is equivalent to fn:number(.).
If $arg is the empty sequence or if $arg or the context item cannot be converted to an xs:double, the xs:double value NaN is returned. If the context item is undefined an error is raised: [err:XPDY0002]XP.
If $arg is the empty sequence, NaN is returned. Otherwise, $arg, or the context item after atomization, is converted to an xs:double following the rules of 17.1.3.2 Casting to xs:double. If the conversion to xs:double fails, the xs:double value NaN is returned.

Arguments:

Type	Description
xs:anyAtomicType?	Value to convert to number

Return type: xs:double

W3C Documentation reference

Returns the absolute value of $arg. If $arg is negative returns -$arg otherwise returns $arg. If type of $arg is one of the four numeric types xs:float, xs:double, xs:decimal or xs:integer the type of the result is the same as the type of $arg. If the type of $arg is a type derived from one of the numeric types, the result is an instance of the base numeric type.
For xs:float and xs:double arguments, if the argument is positive zero or negative zero, then positive zero is returned. If the argument is positive or negative infinity, positive infinity is returned.
For detailed type semantics, see Section 7.2.3 The fn:abs, fn:ceiling, fn:floor, fn:round, and fn:round-half-to-even functions.

Arguments:

Type	Description
numeric?	$arg

Return type: numeric?

Examples:

Query	Result
abs(-2)	2
abs(2137)	2137

W3C Documentation reference

Returns the smallest (closest to negative infinity) number with no fractional part that is not less than the value of $arg. If type of $arg is one of the four numeric types xs:float, xs:double, xs:decimal or xs:integer the type of the result is the same as the type of $arg. If the type of $arg is a type derived from one of the numeric types, the result is an instance of the base numeric type.
For xs:float and xs:double arguments, if the argument is positive zero, then positive zero is returned. If the argument is negative zero, then negative zero is returned. If the argument is less than zero and greater than -1, negative zero is returned.

Arguments:

Type	Description
numeric?	$arg

Return type: numeric?

Examples:

Query	Result
ceiling(10.5)	11
ceiling(-10.5)	-10
ceiling(10.1)	11

W3C Documentation reference

Returns the largest (closest to positive infinity) number with no fractional part that is not greater than the value of $arg. If type of $arg is one of the four numeric types xs:float, xs:double, xs:decimal or xs:integer the type of the result is the same as the type of $arg. If the type of $arg is a type derived from one of the numeric types, the result is an instance of the base numeric type.
For float and double arguments, if the argument is positive zero, then positive zero is returned. If the argument is negative zero, then negative zero is returned.

Arguments:

Type	Description
numeric?	$arg

Return type: numeric?

Examples:

Query	Result
floor(10.5)	10
floor(-10.5)	-11
floor(10.8)	10

W3C Documentation reference

Returns the number with no fractional part that is closest to the argument. If there are two such numbers, then the one that is closest to positive infinity is returned. If type of $arg is one of the four numeric types xs:float, xs:double, xs:decimal or xs:integer the type of the result is the same as the type of $arg. If the type of $arg is a type derived from one of the numeric types, the result is an instance of the base numeric type.
For xs:float and xs:double arguments, if the argument is positive infinity, then positive infinity is returned. If the argument is negative infinity, then negative infinity is returned. If the argument is positive zero, then positive zero is returned. If the argument is negative zero, then negative zero is returned. If the argument is less than zero, but greater than or equal to -0.5, then negative zero is returned. In the cases where positive zero or negative zero is returned, negative zero or positive zero may be returned as [XML Schema Part 2: Datatypes Second Edition] does not distinguish between the values positive zero and negative zero.
For the last two cases, note that the result is not the same as fn:floor(x+0.5).

Arguments:

Type	Description
numeric?	$arg

Return type: numeric?

Examples:

Query	Result
round(10.5)	11
round(10.4999)	10
round(-10.5)	-10

W3C Documentation reference

The value returned is the nearest (that is, numerically closest) value to $arg that is a multiple of ten to the power of minus $precision. If two such values are equally near (e.g. if the fractional part in $arg is exactly .500...), the function returns the one whose least significant digit is even.
If the type of $arg is one of the four numeric types xs:float, xs:double, xs:decimal or xs:integer the type of the result is the same as the type of $arg. If the type of $arg is a type derived from one of the numeric types, the result is an instance of the base numeric type.
The first signature of this function produces the same result as the second signature with $precision=0.
For arguments of type xs:float and xs:double, if the argument is NaN, positive or negative zero, or positive or negative infinity, then the result is the same as the argument. In all other cases, the argument is cast to xs:decimal, the function is applied to this xs:decimal value, and the resulting xs:decimal is cast back to xs:float or xs:double as appropriate to form the function result. If the resulting xs:decimal value is zero, then positive or negative zero is returned according to the sign of the original argument.
Note that the process of casting to xs:decimal may result in an error [err:FOCA0001].
If $arg is of type xs:float or xs:double, rounding occurs on the value of the mantissa computed with exponent = 0.

Arguments:

Type	Description
numeric?	$arg
numeric?	$precision (Optional)

Return type: numeric?

Examples:

Query	Result
round-half-to-even(0.5)	0
round-half-to-even(1.5)	2
round-half-to-even(2.5)	2
round-half-to-even(2.6)	3

W3C Documentation reference

fn:data takes a sequence of items and returns a sequence of atomic values.
The result of fn:data is the sequence of atomic values produced by applying the following rules to each item in $arg:

• If the item is an atomic value, it is returned.
• If the item is a node:
  • If the node does not have a typed value an error is raised [err:FOTY0012].
  • Otherwise, fn:data() returns the typed value of the node as defined by the accessor function dm:typed-value in Section 5.15 typed-value AccessorDM.

Arguments:

Type	Description
item*	Items to convert.

Return type: xs:anyAtomicType*

Examples:

Query	Result
data(/l:library/l:readerList/p:person[1])	7321 Adam Choke

W3C Documentation reference

If the timezone argument is empty, it returns a date without a timezone. Otherwise, it returns a date with a timezone
Arguments and return type:

Type	Description
date	date to be adjusted
timezone	timezone to be imposed into date

Examples:

Expression	Result
adjust-date-to-timezone(xs:date('2011-11-15'), xs:dayTimeDuration("PT10H"))	2011-11-15+10:00

W3C Documentation reference: #func-adjust-date-to-timezone

The fn:error function is a general function that may be invoked as above but may also be invoked from [XQuery 1.0: An XML Query Language] or [XML Path Language (XPath) 2.0] applications with, for example, an xs:QName argument.
W3C Documentation reference

Provides an execution trace intended to be used in debugging queries.
The input $value is returned, unchanged, as the result of the function. In addition, the inputs $value, converted to an xs:string, and $label may be directed to a trace data set. The destination of the trace output is ·implementation-defined·. The format of the trace output is ·implementation dependent·. The ordering of output from invocations of the fn:trace() function is ·implementation dependent·.
Arguments:

Type	Description
item*	$value
xs:string	$label

Return type: item


W3C Documentation reference

Returns a Boolean value indicating whether the argument node is nilled

W3C Documentation reference: #func-nilled

Returns the position of the last node in the context list

W3C Documentation reference: Node-Set-Functions

The boolean function converts its argument to a boolean as follows:

• a number is true if and only if it is neither positive or negative zero nor NaN
• a node-set is true if and only if it is non-empty
• a string is true if and only if its length is non-zero
• an object of a type other than the four basic types is converted to a boolean in a way that is dependent on that type

Arguments and return type:

Type	Description
object	The object to convert to a boolean

Examples:

Expression	Result
boolean("Release11")	true
boolean("")	false

W3C Documentation reference: Boolean-Functions

Returns the string representation of the object argument
Arguments and return type:

Type	Description
string	The object to convert to a string

Examples:

Expression	Result
string((1<0))	false
string(.11)	0.11

W3C Documentation reference: String-Functions

The number function converts its argument to a number as follows:

• a string that consists of optional whitespace followed by an optional minus sign followed by a Number followed by whitespace is converted to the IEEE 754 number that is nearest (according to the IEEE 754 round-to-nearest rule) to the mathematical value represented by the string; any other string is converted to NaN
• boolean true is converted to 1; boolean false is converted to 0
• a node-set is first converted to a string as if by a call to the string function and then converted in the same way as a string argument
• an object of a type other than the four basic types is converted to a number in a way that is dependent on that type

Arguments and return type:

Type	Description
object	The object to convert to a number

Examples:

Expression	Result
boolean("Release11")	true
boolean("")	false

W3C Documentation reference: Numeric-Functions

If the timezone argument is empty, it returns a date without a timezone. Otherwise, it returns a date with a timezone
Arguments and return type:

Type	Description
date	date to be adjusted
timezone	timezone to be imposed into date

Examples:

Expression	Result
adjust-date-to-timezone(xs:date('2011-11-15'), xs:dayTimeDuration("PT10H"))	2011-11-15+10:00

W3C Documentation reference: #func-adjust-date-to-timezone

https://www.w3.org/TR/xpath-functions/#func-error

W3C Documentation reference: #func-error

Returns a Boolean value indicating whether the argument node is nilled

W3C Documentation reference: #func-nilled

Applies function item to every element in sequence

W3C Documentation reference: #func-for-each