Regular Expression Examples

The following examples show some regular expressions and describe what they match:
Expression
Description
[\?&]value= 
A URL parameter value in a URL.
[A-Z]:(\\[A-Z0-9_]+)+ 
An uppercase DOS/Windows full path that (a) is not the root of a drive, and (b) has only letters, numbers, and underscores in its text.
[A-Za-z][A-Za-z0-9_]* 
A ColdFusion variable with no qualifier.
([A-Za-z][A-Za-z0-9_]*)(\.[A-Za-z][A-Za-z0-9_]*)? 
A ColdFusion variable with no more than one qualifier; for example, Form.VarName, but not Form.Image.VarName.
(\+|-)?[1-9][0-9]* 
An integer that does not begin with a zero and has an optional sign.
(\+|-)?[1-9][0-9]*(\.[0-9]*)? 
A real number.
(\+|-)?[1-9]\.[0-9]*E(\+|-)?[0-9]+ 
A real number in engineering notation.
a{2,4} 
Two to four occurrences of "a": aa, aaa, aaaa.
(ba){3,} 
At least three "ba" pairs: bababa, babababa, and so on..

Regular expressions in CFML

The following examples of CFML show some common uses of regular expression functions:
Expression
Returns
REReplace (CGI.Query_String, "CFID=[0-9]+[&]*", "") 
The query string with parameter CFID and its numeric value stripped out.
REReplace("I Love Jellies", "[[:lower:]]","x","ALL" 
I Lxxx Jxxxxxx
REReplaceNoCase("cabaret","[A-Z]", "G","ALL") 
GGGGGGG
REReplace (Report, "\$[0-9,]*\.[0-9]*", "$***.**")", "") 
The string value of the variable Report with all positive numbers in the dollar format changed to "$***.**".
REFind ("[Uu]\.?[Ss]\.?[Aa}\.?", Report ) 
The position in the variable Report of the first occurrence of the abbreviation USA. The letters can be in either case and the abbreviation can have a period after any letter.
REFindNoCase("a+c","ABCAACCDD") 
4
REReplace("There is is coffee in the the kitchen","([A-Za-z]+)
[ ]+\1","*","ALL") 
There * coffee in * kitchen
REReplace(report, "<[^>]*>", "", "All") 
Removes all HTML tags from a string value of the report variable.