Kvalley Computers and Internet -- RegEx Evaluator

Regular Expression
String to Check
Create Variant Expression   Exclude Actual Word   Whitespace:                   
 

Position Matching

Symbol Function
^ Only match the beginning of a string.

"^A" matches first "A" in "An A+ for Anita."
$ Only match the ending of a string.

"t$" matches the last "t" in "A cat in the hat"
\b Matches any word boundary.

"ly\b" matches "ly" in "possibly tomorrow."
\B Matches any non-word boundary.

Literals

Symbol Function
Alphanumeric Matches alphabetical and numerical characters literally.
\n Matches a new line.
\f Matches a form feed.
\r Matches carriage return.
\t Matches horizontal tab.
\v Matches vertical tab.
\? Matches ?
\* Matches *
\+ Matches +
\. Matches .
\| Matches |
\{ Matches {
\} Matches }
\\ Matches \
\[ Matches [
\] Matches ]
\( Matches (
\) Matches )
\xxx Matches the ASCII character expressed by the octal number xxx.

"\50" matches "(" or chr (40).
\xdd Matches the ASCII character expressed by the hex number dd.

"\x28" matches "(" or chr (40).
\uxxxx Matches the ASCII character expressed by the UNICODE xxxx.

"\u00A3" matches "£".
Character Classes
Symbol Function
[xyz] Match any one character enclosed in the character set.

"[a-e]" matches "b" in "basketball".
[^xyz] Match any one character not enclosed in the character set.

"[^a-e]" matches "s" in "basketball".
. Match any character except \n.
\w Match any word character. Equivalent to
[a-zA-Z_0-9].
\W Match any non-word character. Equivalent to [^a-zA-Z_0-9].
\d Match any digit. Equivalent to [0-9].
\D Match any non-digit. Equivalent to [^0-9].
\s Match any space character. Equivalent to
[ \t\r\n\v\f].
\S Match any non-space character. Equivalent to [^ \t\r\n\v\f].
Repetition
Symbol Function
{x} Match exactly x occurrences of a regular expression.

"\d{5}" matches 5 digits.
{x,} Match x or more occurrences of a regular expression.

"\s{2,}" matches at least 2 space characters.
{x,y} Matches x to y number of occurrences of a regular expression.

"\d{2,3}" matches at least 2 but no more than 3 digits.
? Match zero or one occurrences. Equivalent to {0,1}.

"a\s?b" matches "ab" or "a b".
* Match zero or more occurrences. Equivalent to {0,}.
+ Match one or more occurrences. Equivalent to {1,}.
Alternation & Grouping
Symbol Function
() Grouping a clause to create a clause. May be nested. "(ab)?(c)" matches "abc" or "c".
| Alternation combines clauses into one regular expression and then matches any of the individual clauses.

"(ab)|(cd)|(ef)" matches "ab" or "cd" or "ef".
BackReferences
Symbol Function
()\n Matches a clause as numbered by the left parenthesis.

"(\w+)\s+\1" matches any word that occurs twice in a row, such as "hubba hubba."
(?!) Negative Lookahead.

"^(?!ver)v" matches any word starting with"v" except if the word starts with "ver".