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# XPath Standard Functions

The Publisher supports the following XPath standard functions. In addition, there are the Publisher-specific layout functions and user-defined functions.

## Strings

`concat(<value>,<value>, ...)`
  Create a new text by concatenating the values.
`contains(<haystack>,<needle>)`
  True if haystack contains needle. Example: `contains('bana','na')` returns `true()`.
`starts-with(<string>, <string>)`
  True if the first string starts with the second.
`ends-with(<string>, <string>)`
  True if the first string ends with the second.
`substring(<input>,<start>[,<length>])`
  Return a part of the string. `substring('Goldfarb', 5, 3)` returns `far`. `start` can be negative (counts from the end).
`substring-before(<string>,<string>)`
  Return the part of the first string before the second. Example: `substring-before("tattoo", "attoo")` returns `"t"`.
`substring-after(<string>,<string>)`
  Return the part of the first string after the second. Example: `substring-after("tattoo", "tat")` returns `"too"`.
`string-length(<string>)`
  Return the length of the string. Multi-byte UTF-8 sequences count as one.
`string-join(<sequence>, <separator>)`
  Join the elements of the sequence with the separator.
`normalize-space(<text>)`
  Remove leading and trailing whitespace. Multiple spaces and newlines are replaced by a single space.
`upper-case(<text>)`
  Convert text to uppercase. `upper-case('text')` returns `TEXT`.
`lower-case(<text>)`
  Convert text to lowercase. `lower-case('Text')` returns `text`.
`translate(<input>,<from>,<to>)`
  Replace all characters in `input` found in `from` with the corresponding character in `to`. Example: `translate('banana','an','uo')` returns `buouou`. If `to` is shorter than `from`, extra characters are deleted.
`matches(<text>,<regexp>[,<flags>])`
  True if the text matches the regular expression. Flags: `s`, `i`, `m` (see XPath spec). Example: `matches("banana", "^(.a)+$")` returns true.
`replace(<input>,<regexp>,<replacement>)`
  Replace all matches of the regular expression with the replacement text. Example: `replace('banana', 'a', 'o')` returns `bonono`. With groups: `replace('W151TBH','^[A-Z]([0-9]+)[A-Z]+$', '$1')` returns `151`.
`tokenize(<input>,<regexp>)`
  Split the input by the regular expression into a sequence of strings. Example: `tokenize("Go home, Jack!", "\W+")` returns the sequence `"Go", "home", "Jack", ""`.
`string(<sequence>)`
  Return the text value of the sequence.
`codepoints-to-string(<codepoints>)`
  Convert a sequence of codepoints to a string.
`string-to-codepoints(<string>)`
  Convert a string to a sequence of codepoints.

## Numbers

`number(<value>)`
  Convert the value to a number. Returns NaN if conversion fails.
`abs(<number>)`
  Return the absolute value. `abs(-1.34)` returns `1.34`.
`ceiling(<number>)`
  Round up to the next integer. `ceiling(1.34)` returns `2`.
`floor(<number>)`
  Round down to the next integer. `floor(1.7)` returns `1`.
`round(<number>[,<decimals>])`
  Round to the given number of decimal places (default: 0).
`round-half-to-even(<number>[,<decimals>])`
  Banker’s rounding: at .5, round to the nearest even number.
`format-number(<number>, <pattern>)`
  Format the number according to the pattern. Example: `format-number(12345.67, '#,##0.00')` returns `12,345.67`.
`max(<sequence>)`
  Return the maximum. `max((1.1, 2.2, 3.3))` returns `3.3`.
`min(<sequence>)`
  Return the minimum. `min((1.1, 2.2, 3.3))` returns `1.1`.

## Boolean Functions

`true()`
  Return true.
`false()`
  Return false.
`not(<value>)`
  Negate the boolean value. `not(true())` returns `false()`.
`boolean(<sequence>)`
  Return the effective boolean value.
`empty(<sequence>)`
  True if the sequence is empty (e.g. a non-existing attribute or element).

## Sequences and Nodes

`count(<nodes>)`
  Count child elements with the given name. Example: `count(article)`.
`position()`
  Return the position of the current node.
`last()`
  Return the number of same-named sibling elements.
`distinct-values(<sequence>)`
  Return unique values. `distinct-values((1,2,2,3))` returns `(1,2,3)`.
`reverse(<sequence>)`
  Reverse the order of the sequence.
`local-name()`
  Return the name of the current node (without namespace).
`name()`
  Return the name of the current node (with namespace prefix).
`namespace-uri([<nodeset>])`
  Return the namespace URI of the first node.
`root(<element>)`
  Return the root element.
`doc(<filename>)`
  Open the file and return its content as an XML tree.
`serialize(<node>)`
  Return the XML serialization of the node as a string. Example: if the current element is `<item color="red">Text</item>`, `serialize(.)` returns the string `<item color="red">Text</item>`. Special characters are properly escaped (`&amp;`, `&lt;`, `&gt;`, `&quot;`).
`unparsed-text(<filename>)`
  Return the file content as uninterpreted text.

## Arrays and maps

The functions in the `array:` and `map:` namespaces are described in the chapter Arrays and Maps, together with the required namespace declarations and examples.

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