User Guide

146 Chapter 7: Using Regular Expressions in Functions
Using special characters
Regular expressions define the following list of special characters:
+ * ? . [ ^ $ ( ) { | \
In some cases, you use a special character as a literal character. For example, if you want to search
for the plus sign in a string, you have to escape the plus sign by preceding it with a backslash:
"\+"
The following table describes the special characters for regular expressions:
Special
Character
Description
\ A backslash followed by any special character matches the literal character itself, that is,
the backslash escapes the special character.
For example, "\+" matches the plus sign, and "\\" matches a backslash.
. A period matches any character, including newline.
To match any character except a newline, use [^#chr(13)##chr(10)#], which excludes
the ASCII carriage return and line feed codes. The corresponding escape codes are \r
and \n.
[ ] A one-character character set that matches any of the characters in that set.
For example, "[akm]" matches an “a”, “k”, or “m”. A hyphen in a character set indicates
a range of characters; for example, [a-z] matches any single lowercase letter.
If the first character of a character set is the caret (^), the regular expression matches any
character except those in the set. It does not match the empty string.
For example, [^akm] matches any character except “a”, “k”, or “m”. The caret loses its
special meaning if it is not the first character of the set.
^ If the caret is at the beginning of a regular expression, the matched string must be at the
beginning of the string being searched.
For example, the regular expression "^ColdFusion" matches the string "ColdFusion lets
you use regular expressions" but not the string "In ColdFusion, you can use regular
expressions."
$ If the dollar sign is at the end of a regular expression, the matched string must be at the
end of the string being searched.
For example, the regular expression "ColdFusion$" matches the string "I like
ColdFusion" but not the string "ColdFusion is fun."
? A character set or subexpression followed by a question mark matches zero or one
occurrences of the character set or subexpression.
For example, xy?z matches either “xyz” or “xz”.
| The OR character allows a choice between two regular expressions.
For example, jell(y|ies) matches either “jelly” or “jellies”.
+ A character set or subexpression followed by a plus sign matches one or more
occurrences of the character set or subexpression.
For example, [a-z]+ matches one or more lowercase characters.
* A character set or subexpression followed by an asterisk matches zero or more
occurrences of the character set or subexpression.
For example, [a-z]* matches zero or more lowercase characters.