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Version: 4.11.2

Using xpath expression language in Dovetail

Xpath expression is supported by the following components:

Selecting nodes​

General​

ExpressionDescription
nodenameSelects all nodes with the name "nodename"
/Selects from the root node
//Selects nodes in the document from the current node that match the selection no matter where they are
.Selects the current node
..Selects the parent of the current node
@Selects attributes

Things to keep in mind​

  • Use *: to ignore namespaces

Examples​

This xml is used in the examples below.

<?xml version="1.0" encoding="utf-8"?>
<orders>
	<order>
		<header orderid="123">
			<ordernr>12345</ordernr>
			<datetime>2019-04-27T08:58:40.375Z</datetime>
		</header>
		<orderlines>
			<orderline>
				<item>1</item>
				<value>50</value>
			</orderline>
			<orderline>
				<item>2</item>
				<value>100</value>
			</orderline>
			<orderline>
				<item>3</item>
				<value>150</value>
			</orderline>
		</orderlines>
	</order>
</orders>

Function examples​

Selects path from the root node​

Expression: /orders/order/header

Result:

<header orderid="123">
    <ordernr>12345</ordernr>
    <datetime>2019-04-27T08:58:40.375Z</datetime>
</header>

Selects nodes in the document from the current node that match the selection no matter where they are​

Expression: //ordernr

Result:

<ordernr>12345</ordernr>

Selects the textual value of first ordernr element​

Expression: //ordernr/text()

Result:

12345

Selects attribute orderid​

Expression: //@orderid

Result:

orderid=123

Matches any attribute node​

Expression: //@*

Result:

orderid=123

Selects all header elements which have at least one attribute of any kind​

Expression: //header[@*]

Result:

<header orderid="123">
	<ordernr>12345</ordernr>
	<datetime>2019-04-27T08:58:40.375Z</datetime>
</header>

Computes two node-sets with |​

Expression: //ordernr | //orderline/value

Result:

<ordernr>12345</ordernr>
<value>50</value>
<value>100</value>
<value>150</value>

Returns a sequence of items from the position specified by the start argument and position​

Expression: subsequence(//orderline/value,1)

Result:

<value>50</value>
<value>100</value>
<value>150</value>

Returns the reversed order of the items specified​

Expression: reverse(//orderline/value)

Result:

<value>150</value>
<value>100</value>
<value>50</value>

Returns the positions within the sequence of items that are equal to the search item argument​

Expression: index-of(//orderline/value/text(),"100")

Result:

2

Returns the argument that is greater than the others​

Expression: max(//orderline/item)

Result:

3

Returns the argument that is less than the others​

Expression: min(//orderline/item)

Result:

1

Returns the count of nodes​

Expression: count(//orderlines/orderline/item)

Result:

3

Returns the sum of the numeric value of each node in the specified node-set​

Expression: sum(//order/orderlines/orderline/value)

Result:

300

Returns the average of the argument values​

Expression: avg(//order/orderlines/orderline/value)

Result:

100

Returns the length of the specified string​

Expression: string-length(//ordernr[1]/text())

Result:

5

Returns the name of the current node or the first node in orders​

Expression: name(//orders/*[1])

Result:

order

Returns a string that is created by replacing the given pattern with the replace argument​

Expression: replace(name(//orders/*[1]),"e","a")

Result:

ordar

Returns the current dateTime (with timezone)​

Expression: current-dateTime()

Result:

2019-05-03T10:23:18.246Z

Returns an integer that represents the year component in the localized value of the argument​

Expression: year-from-dateTime(//datetime/text())

Result:

2019

Returns an integer that represents the month component in the localized value of the argument​

Expression: month-from-dateTime(//datetime/text())

Result:

4

Returns an integer that represents the day component in the localized value of the argument​

Expression: day-from-dateTime(//datetime/text())

Result:

27

Selects the first orderline element that is the child of the orderlines element​

Expression: //orderlines[1]

Result:

<orderline>
	<item>1</item>
	<value>50</value>
</orderline>

Selects the last ‘orderline’ element that is the child of the ‘orderlines’ element​

Expression: //orderlines/orderline[last()]

Result:

<orderline>
	<item>3</item>
	<value>150</value>
</orderline>

Selects the last but one ‘orderline’ element that is the child of the orderlines element​

Expression: //orderlines/orderline[last()-1]

Result:

<orderline>
	<item>2</item>
	<value>100</value>
</orderline>

Selects the first two orderline elements that are children of the orderlines element​

Expression: //orderlines/orderline[position()<3]

Result:

<orderline>
	<item>1</item>
	<value>50</value>
</orderline>
<orderline>
	<item>2</item>
	<value>100</value>
</orderline>

Operators​

OperatorDescription
|Computes two node-sets
+Addition
-Subtraction
*Multiplication
divDivision
=Equal
!=Not equal
<Less than
<=Less than or equal to
>Greater than
>=Greater than or equal to
oror
andand
modModulus (division remainder)

Operator examples​

Expression
max(//orderline/item)>5
max(//orderline/item)+min(//orderline/item)=4

Useful references​

For more detailed information go to: