fn:replace

The fn:replace function replaces parts of a string that match a regular expression. The regular expression syntax used is defined by XML Schema with a few modifications/additions in XQueryXPath/XSLT. The $pattern argument is a regular expression. While it is nice to have the power of regular expressions, if you simply want to replace a particular sequence of characters you don't have to be familiar with regular expressions to do that; you can just specify the string you want replaced for $pattern, as long as it doesn't contain any special characters.

The $replacement argument specifies a string (not a pattern) that is to be used as a replacement.

The $flags argument allows for additional options in the interpretation of the regular expression, such as multi-line processing and case insensitivity. Flags, reluctant quantifiers and sub-expressions are features that are covered.

For more examples of XQueryXPath/XSLT/XML Schema regular expressions, 

This description is © Copyright 2007, O'Reilly Media. It is excerpted from the book XQuery by Priscilla Walmsley, O'Reilly, 2007. For a complete explanation of this function, please refer to Appendix A of the book.

Arguments and Return Type

Name	Type	Description
$input	xs:string?	the string to change
$pattern	xs:string	regular expression to match the areas to be replaced
$replacement	xs:string	the replacement string
$flags	xs:string	flags that control multiline mode, case insensitivity, etc.
return value	xs:string

Examples

XQuery Example	Results
replace('query', 'r', 'as')	queasy
replace('query', 'qu', 'quack')	quackery
replace('query', '[ry]', 'l')	quell
replace('query', '[ry]+', 'l')	quel
replace('query', 'z', 'a')	query
replace('query', 'query', '')	zero-length string
replace( (), 'r', 'as')	zero-length string
replace('query', 'r?', 'as')	Error FORX0003
replace('query', '(r', 'as')	Error FORX0002
replace('Chapter', '(Chap)|(Chapter)', 'x')	xter
The following examples show the difference between reluctant and regular quantifiers:
replace('reluctant', 'r.*t', 'X')	X
replace('reluctant', 'r.*?t', 'X')	Xant
replace('aaah', 'a{2,3}', 'X')	Xh
replace('aaah', 'a{2,3}?', 'X')	Xah
replace('aaaah', 'a{2,3}', 'X')	Xah
replace('aaaah', 'a{2,3}?', 'X')	XXh
The following examples exhibit the use of sub-expressions:
replace('Chap 2...Chap 3...Chap 4...', 'Chap (\d)', 'Sec $1.0')	Sec 2.0...Sec 3.0...Sec 4.0...
replace('abc123', '([a-z])', '$1x')	axbxcx123
replace('2315551212', '(\d{3})(\d{3})(\d{4})', '($1) $2-$3')	(231) 555-1212
replace('2006-10-18', '\d{2}(\d{2})-(\d{2})-(\d{2})', '$2/$3/$1')	10/18/06
replace('25', '(\d+)', '\$$1.00')	$25.00