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Get number from xpath

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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.

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XPath Tester / Evaluator

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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. The syntax is the same in both cases. In the Java interface, expressions are encapsulated by the net. Expression class, and are parsed using a call such as Expression.

To exploit the full power of XPath expressions in the Java API, you will need to supply some support classes to perform functions such as resolving namespace references: this cannot be done automatically because there is no stylesheet to use as a reference point.

An important change in XPath 2. A sequence consists of zero or more items; an item may be a node or a simple-value. Examples of simple-values are integers, strings, booleans, and dates not supported yet in Saxon. A single value such as a number is considered as a sequence of length 1.

The empty sequence is written as ; a singleton sequence may be written as "a" or "a" , and a general sequence is written as "a", "b", "c". The node-sets of XPath 1. Path expressions will return node sequences whose nodes are in document order with no duplicates, but other kinds of expression may return sequences of nodes in any order, with duplicates permitted.

String literals are written as "London" or 'Paris'. In each case you can use the opposite kind of quotation mark within the string: 'He said "Boo"', or "That's rubbish". In a stylesheet XSL expressions always appear within XML attributes, so it is usual to use one kind of delimiter for the attribute and the other kind for the literal.

Anything else can be written using XML character entities. From Saxon 7. Numeric constants follow the Java rules for decimal literals: for example, 12 or 3. Also, note that you may need a space before the minus sign to avoid it being treated as a hyphen within a preceding name. The numeric literal is taken as a double precision floating point number if it uses scientific notation e. Decimal values in Saxon have unlimited precision, integers are limited to 64 bits.

Constants of other data types can be written using constructors, which look like function calls but require a string literal as their argument. For example, float " Saxon implements constructors for many of the data types defined in XML Schema Part 2, but most of them are essentially dummy implementations at present.

Two exceptions are for date and dateTime values: for example you can write constants for these data types as date "" or dateTime "TZ". The variable is always evaluated at the textual place where the expression containing it appears; for example a variable used within an xsl:attribute-set must be in scope at the point where the attribute-set is defined, not the point where it is used. A variable may take a value of any data type, and in general it is not possible to determine its data type statically.

Starting with XPath 2. The expressions that declare variables are the for , some , and every expressions. If parentheses are not used, operator precedence follows the sequence below, starting with the operators that bind most tightly.

Within each group the operators are evaluated left-to-right. The operators eq, ne, lt, le, gt, ge are also available: the precedence of these may not be correct, so use parentheses to be safe.

There are some constructs that are specifically string expressions, but in addition any other kind of expression can be used in a context where a string expression is required:. There are some constructs that are specifically numeric expressions, but in addition any string whose value is convertible to a number can be used as a number.

A string that does not represent any number is treated as the double value NaN not a number. Expressions of other types are converted to booleans as follows: Numeric values: 0 is treated as false, everything else as true. String values: the zero-length string is treated as false, everything else as true. Note this changes in XPath 2. Sequences: the empty sequence is treated as false. A sequence consisting of a single boolean is treated as the value of that boolean.

A sequence containing at least one node is treated as true. Converting any other sequence throws an error. The optional-predicates is a sequence of zero-or-more predicates, each enclosed in square brackets, each being either a boolean expression or a numeric expression as a shorthand for testing position. For example, treat as xsd:integer my:func is a way of telling the system that my:func is expected to return an integer. Saxon also implements the instance of operator which tests whether a value is of a specified type.

Michael H. Kay 30 April This performs an explicit type conversion to a string, which will always give the same result as the implicit conversion described above.

The main case where explicit conversion is useful is when assigning a value to a variable. This concatenates the string values of the arguments. There may be any number of arguments two or more. This extracts a substring of the string value of expression1. Expression2 gives the start position starting at 1 , expression 3 gives the length: if omitted, the rest of the string is used. For example, substring "Michael", 2, 4 is "icha".

This returns the substring of expression1 that precedes the first occurrence of expression2. If expression1 does not contain expression2, it returns the empty string. This returns the substring of expression1 that follows the first occurrence of expression2.

This removes leading and trailing white space, and converts all other sequences of white space to a single space character. This replaces any character in expression1 that also occurs in expression2 with the corresponding character from expression3. If there is no corresponding character in expression3 because it is shorter than expression2 , the character is removed from the string.

Returns n occurrences of the string, concatenated. For example, string-pad "ab", 3 returns "ababab". Returns the name of the given node, or the current node if the argument is omitted. The name here is the "display name"; it will use the same namespace prefix as in the original source document. Returns the local part after the colon of the name of the given node, or the current node if the argument is omitted. Returns the URI of the namespace of the name of the given node, or the current node if the argument is omitted.

Returns the URI of the unparsed entity with the given name in the current document, if there is one; otherwise the empty string. Returns a system-generated identifier for the given node, or the current node if the argument is omitted. The generated identifiers are always alphanumeric except for the document node, where the identifier is the empty string. This performs an explicit type conversion to a number, which will always give the same result as the implicit conversion described above.

Explicit conversion can be useful when assigning a value to a variable. It is also useful when creating an qualifier in a nodeset expression, since the meaning of a numeric qualifier is different from a boolean one. At present in Saxon this always converts to a double.

This converts the value of each item in the sequence to a number, and totals the result. This converts the value of each item in the sequence to a number, and returns the average of the result. This converts the value of each item in the sequence to a number, and returns the minimum the result. This converts the value of each item in the sequence to a number, and returns the maximum the result.

This returns the number of characters in the string value of expression. Characters are counted using the Java length function, which does not necessarily give the same answer as the XPath rules, particularly when combining characters are used. This performs an arithmetic operation on the two values. Note that div currently does a floating-point division, and mod also uses floating point. The other operators are evaluated according to the data type of their operands, for example adding two integers gives an integer, adding an integer to a decimal gives a decimal.

This returns the closest integer to the argument. The rounding rules follow Java conventions which are not quite the same as the XSL rules. This returns the position of the current item in the list of items being processed. Positions are numbered from one. This performs an explicit type conversion to a boolean, which will always give the same result as the implicit conversion described above. These operators perform boolean conjunction and disjunction.

Saxon currently implements them with three-valued logic as in SQL, though this is not in sync with the XPath Working Draft as published. This returns the logical negation of the argument, but adapted to use three-valued logic as in SQL. The difference is that not is true, whereas not3 is. Note that the empty sequence, , plays the same rule as the null value in SQL.

This tests whether the two values are equal or not-equal. More strictly, it considers both operands as sequences, and returns true if there is a value in the first sequence that is equal not-equal to some value in the second sequence.

This tests whether the two nodes are identical or not-identical. The operands must be single nodes.

XPath - Number Operators / Functions

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. Learn more.

This content cannot be displayed without JavaScript. Please enable JavaScript and reload the page. Fonto uses XPath 3.

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.

XPath and XPointer by John Simpson

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.

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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. The syntax is the same in both cases.

Please check the errata for any errors or issues reported since publication. See also translations.

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. If the string contains one or more semicolons then everything that precedes the last semicolon is taken as the primary format token and everything that follows is taken as the format modifier; if the string contains no semicolon then the entire picture is taken as the primary format token, and the format modifier is taken to be absent which is equivalent to supplying a zero-length string.

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.

SEE VIDEO BY TOPIC: Xpath in Selenium - Selenium Xpath Tutorial - Selenium Xpath Examples - Selenium Training - Edureka

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.

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An XPath expression returns either a node-set, a string, a Boolean, or a number. XPath Operators. Below is a list of the operators that can be used in XPath.

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