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Get number from xpath

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These extended functions provide additional functionality that is useful to create behaviors, but does not conform to the XPath standard. The XPath function library is divided into four groups, each of which is described in more detail, below:. Node set functions - for working with node-sets, either the implicit current node set or one passed as a parameter. Boolean functions : For working with Booleans, including type coercions. Returns the non-namespace portion of the node name of either a node set passed as a parameter or the current node in the current node set. Returns the namespace URI of the node name of either a node set passed as a parameter or the current node in the current node set.

SEE VIDEO BY TOPIC: How to Find Xpath In Chrome for selenium automation scripts


XPath Tester / Evaluator

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The XPath 1. When I was a kid, I loved watching my father work on cars. The objective was the get the gap just right, to ensure that the spark plug fired in just exactly the right way.

A function in computer-language terms is like a spark-plug gapper. Almost without exception, regardless of the computer language in question, functions are represented syntactically the same way:. Depending on the function, you may pass one or more arguments to it, which change its behavior in various ways.

The arguments are enclosed in parentheses. Thus, the spark-plug gapper might be represented like this:. In this form, the function syntax is called a prototype. So an actual call to our hypothetical gapper function might look like this:. Now, many functions are fussy about both the number of arguments and the type. Depending on how the gapper function is written, for example, the following might be illegal calls to it:.

If in fact a legal call to gapper passes only a single numeric argument, either of these two calls will fail — probably resulting in an error message of some kind. That is, a function returns a value. Set the gap on this plug to fifteen-thousandths of an inch. In a hypothetical computer language to achieve this purpose, this English-language instruction might be rendered:.

That is, in formal terms, the gapper function, when passed a numeric value of 1, returns the numeric value. Now, though, most spark-plug gaps are expressed in terms of millimeters. The hypothetical computer-language expression of this might look something like:. The gapper function here still returns. These categories are node-set, string, Boolean, and numeric functions. Argument is a string value, to be enclosed in quotation marks in the function call.

Argument is a node-set, represented by an XPath location path. Argument has a Boolean value of true or false. Argument has a numeric value.

Argument can be any of several types. For instance, you can pass certain functions a string or a numeric argument, and the function will handle any necessary data-type conversion.

A question mark appended to one of the above data types means the argument is optional. In such a case, the function will usually assume some default value for the argument, perhaps derived from the context node at the point of the function call. Note that the type of data returned by each function is documented in a table at the start of the section dealing with the appropriate function type.

Unlike functions in some traditional programming languages, XPath functions always return a value. If you need something beyond what this chapter describes, see Appendix A.

A node-set function, as the name implies, operates on a node-set; one of these functions also returns a node-set. Table summarizes the functions in this category. Each function is discussed in detail in a separate subsection following the table. These discussions assume that the source document being referenced by XPath expressions is the following fragment of an XML document:. Returns the local name that is, the QName without a namespace prefix of the first node in nodeset.

Returns the URI associated with the namespace prefix of the first node in nodeset. If the context node-set, at the point of the call to last , contains 12 nodes, last returns Assume the context for the call to last is established by a location path such as the following, referencing the sample XML document above:.

This locates a node-set consisting of two element nodes, book:para and svg. Therefore, a call to last at this point returns the value 2.

These positions begin at 1 for the first node in the node-set and increment up to the value of the last function. Therefore, this location path:. You could locate just the svg node by adding a predicate, as here:. Note that the value returned by the position function is sensitive to the forward or reverse direction of the axis in effect. For forward-type axes, such as descendant:: in the preceding example, nodes are accessed in their natural document order; for reverse-type axes, nodes are accessed in reverse document order.

So we could build a location path beginning, say, at the svg element node and locating the ancestor book:chapter element with a location path such as:. Here, the book:section element is ancestor 1 in reverse document order, and book:chapter is ancestor 2.

That is:. Many XSLT operations must be performed for every n th occurrence of some kind of node in the source tree being transformed. For a simple example, perhaps you want to shade every odd row of a table, leaving the even rows unshaded: in other words, to shade every second row. This kind of processing can be achieved easily using position together with the mod numeric operator. In every respect but one, the count function operates identically to the last function covered earlier.

What makes it different is that count takes one argument; last , none. Thus, count can be used to return the number of nodes in some arbitrary node-set other than the current one. The following XSLT template displays the number of the current section in the chapter within which it appears, then displays using count the total number of book:section nodes in the document as a whole. Here, the outermost xsl:for-each element loops through every book:chapter element; the innermost xsl:for-each element loops through each book:section child of the selected book:chapter.

When you apply this template to a sample document consisting of three book:chapter elements — the first with one book:section child elements, the second with three, and the third with two — the result is:. Unlike the other functions in the node-set category, the id function actually returns a node-set, given its argument. The argument is usually, but not always, a string; see Section 4.

The value of the argument locates the set of all element nodes with the indicated ID-type attribute; because the value of an ID-type attribute, by definition, must be unique within a given document, the resulting node-set thus will contain a single element node or be empty, if no elements have an ID-type attribute with this value.

You can also use a whitespace-delimited list of values to return all element nodes with any matching ID-type attributes. For instance:. If no element nodes match a particular value, no error condition exists.

Such an approach, while perhaps more prosaic, is also closer to failure-proof. XSLT users can also take advantage of keys to ensure unique identifiers. The id function is unique among functions in the XPath spec in one regard.

As with the other functions, if you pass it a value that is not a string, the value is treated as if it had been converted to a string by the string function covered later in this chapter.

Typically, when you pass string a node-set, it returns the string-value of only the first node in the node-set. The local-name function returns the name of a node, shorn of any namespace prefix. You might call this the un-QName. If the optional argument is not supplied, the function operates as if you had passed it a node-set consisting only of the context node.

If the node-set contains more than one node, the function returns the local-name of only the first node in document order in the node-set:. If you omit the optional argument, its default value is a node-set consisting of just the context node. If the node-set passed as the argument consists of more than one node, the function returns the URI associated with only the first node in the node-set. If the specified element or attribute has no associated URI, the function returns an empty string.

The elements with explicit book : prefixes are associated with the URIs tied to those prefixes via the namespace declarations for that prefix. This expression:. An attribute also does not acquire the namespace URI associated with the corresponding element automatically.

For attributes in the sample document such as id , style , and cx , an empty string is returned as the namespace URI. However, this expression:. By the way, as always when dealing with namespaces, remember that the exact namespace prefix is seldom relevant: what counts is the URI to which the namespace prefix is bound.

In such a context, the following two function calls return exactly the same results as long as the document containing the XPath expression binds both prefixes to the same URI:. Therefore, name is truly reliable only when processing elements and attributes in no namespace at all.

As in the other name-related functions, passing no argument at all causes name to operate on a node-set consisting of just the context node; if the node-set argument includes more than one node, the function operates on only the first. On the face of it, using a function such as name might seem superfluous.

For instance, you might need to isolate the n th child of a particular element, displaying its name and the names and values of all its attributes. A portion of such a stylesheet might look something like the following:. I described an algorithm there for computing an expanded-name, consisting of the namespace URI, a plus sign, and the local-name of the node.

The exception is id. Remember too that not only elements and attributes but also PIs have names. In this case, the value returned by the local-name function is identical to the value returned by the name function. Indeed, that is true for all node types except elements and attributes. The value returned by the namespace-uri function when applied to a PI is an empty string.

If the first node in the node-set handled by local-name , namespace-uri , or name is the root node, a comment, or a text node, the returned value is likewise an empty string. Rather bizarrely, in my opinion, namespace nodes have expanded names. The namespace URI for a namespace node is always null. In the sample document, which declares three namespaces in the root element, all elements thus have three namespace nodes associated with them counting the namespace implicitly associated with the built-in xml : prefix ; their expanded names are, respectively, book , xlink , xml , and an empty string.

XPath - Number Operators / Functions

This document is an informal guide to the syntax of XPath 2. For formal specifications, see the XPath 2. This summary has been updated to include brief descriptions of those XPath 2. Saxon expressions may be used either in an XSL stylesheet, or as a parameter to various Java interfaces.

Please check the errata for any errors or issues reported since publication. See also translations. W3C liability , trademark and document use rules apply.

The XPath 1. When I was a kid, I loved watching my father work on cars. The objective was the get the gap just right, to ensure that the spark plug fired in just exactly the right way. A function in computer-language terms is like a spark-plug gapper.

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This website uses cookies. By continuing to browse or login to this website, you consent to the use of cookies. Learn more. Lots of power, and several interesting languages are available for use. You could always call out to a Java class, so that was not all that limiting. With the advent of NSure Identity Manager 2. It is very readable and makes sense in English only, sorry to read, because the tokens, verbs, and nouns are all nicely described by their definition. There are currently two different implementations of it, one in iManager, and the other in Designer for Identity Manager. I personally like the Designer interface better, but that is more of a preference for the widgets and the responsiveness of a thick client Eclipse based versus a web application, that is always, by definition, a little slower to respond.

XPath and XPointer by John Simpson

XPath uses path expressions to select nodes or node-sets in an XML document. The node is selected by following a path or steps. XPath uses path expressions to select nodes in an XML document. The most useful path expressions are listed below:. In the table below we have listed some path expressions with predicates and the result of the expressions:.

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By using our site, you acknowledge that you have read and understand our Cookie Policy , Privacy Policy , and our Terms of Service. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. All of these XPaths will select "" as a string as requested. You could also wrap any of the above expressions with a number function call if you actually want as a number rather than as a string.

Formats an integer according to a given picture string, using the conventions of a given natural language if specified. The rules that follow describe how non-negative numbers are output. The primary format token is always present and must not be zero-length.

XPath 2. Written for professional programmers who use XML every day but find the W3C XPath specifications tough to slog through, this book explains in everyday language what every construct in the language does and how to use it. It also offers background material on the design thinking behind the language, gentle criticism of the language specification when appropriate, and a diverse range of interesting examples in various application areas. Michael Kay. What is this book about? XPath 20 in Context.


Mar 10, - Using XPATH to get the position of a node in a node set: Novell Identity one node, counts the number of nodes till there, and adds one to it.








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