> For the complete documentation index, see [llms.txt](https://upsolver.gitbook.io/content/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://upsolver.gitbook.io/content/reference-1/functions-and-operators/functions/regular-expressions.md). # Regular Expressions This section describes the following regular expression functions:

Function	Description
REGEX_EXTRACT	Finds the first match of the regular expression pattern in string and returns the capturing group number requested
REGEXP_EXTRACT_ALL	Matches the regular expression on the input string. Returns the escape groups if any exist or the original string if none exists
REGEXP_LIKE	Evaluates the regular expression pattern and determines if it is contained within the string
REGEX_MATCH_POSITION	Matches the regular expression on the input string, and returns the index of the first match
REGEX_NAMED_GROUPS	Matches the regular expression on the input string. Returns record with field names and group names
REGEXP_REPLACE	Evaluates the regular expression pattern and replaces every instance found with the replacement

## Regular expression patterns The regular expression patterns used when performing RegEx pattern matches are described in the table below:

Expression	Contact	Description
Any character	.	Matches any single character except a line break.
Zero or more	*	Matches zero or more occurrences of the preceding expression, making all possible matches.
One or more	+	Matches at least one occurrence of the preceding expression.
Beginning of line	^	Anchors the match string to the beginning of a line.
End of line	$	Anchors the match string to the end of a line.
Beginning of word	<	Matches only when a word begins at this point in the text.
End of word	>	Matches only when a word ends at this point in the text.
Line break	\n	Matches a platform-independent line break. In a Replace expression, inserts a line break.
Digits	\d	Matches any digit [0-9].
Any one character in the set	[]	Matches any one of the characters within the []. To specify a range of characters, list the starting and ending character separated by a dash (-), as in [a-z].
Matches any character not in the set of characters following the ^.	[^...]	Matches any character not in the set of characters following the ^.
Or	\|	Matches either the expression before or the one after the OR symbol (\|). Mostly used within a group. For example, (sponge\|mud) bath matches "sponge bath" and "mud bath."
Tagged expression	{}	Matches text tagged with the enclosed expression.
/C++ Identifier	:i	Matches the expression ([a-zA-Z_$][a-zA-Z0-9_$]*).
Quoted string	:q	Matches the expression (("[^"]")\|('[^']')).
Space or Tab	:b	Matches either space or tab characters.
Matches the expression ([0-9]+).	:z	Integer :z Matches the expression ([0-9]+).

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