Regular Expression Online Tool

Regular Expression Online Tool

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Match

Replace - Side by Side

Replace - Stacked

Command

Library

Special Characters

.
Match any character except newline
1234
\w
Match any alphanumeric character
\s
Match any whitespace character
\d
Match any digit
\b
Match the beginning or end of a word
^
Match the beginning of the string
$
Match the end of the string

Escaped characters

\\
Match special character "\"
\.
Match special character "."
\$
Match special character "$"
\^
Match special character "^"
\(
Match special character "("
\)
Match special character ")"
\{
Match special character "{"
\}
Match special character "}"
\[
Match special character "["
\]
Match special character "]"

Repetitions

*
Repeat any number of times
+
Repeat one or more times
?
Repeat zero or one time
{n}
Repeat n times
{n,m}
Repeat at least n, but no more than m times
{n,}
Repeat at least n times

Character Classes

[a-z]
match any lowercase letter of the alphabet
[a-zA-Z]
match any letter of the alphabet
[0-9]
match any digit
[0-9a-fA-F]
match any Hex
[\(\[\{]
match any of "(", "[" or "{"

Negation

\W
Match any character that is NOT alphanumeric
\D
Match any character that is NOT whitespace
\S
Match any character that is NOT a digit
\B
Match a position that is NOT the beginning or end of a word
[^aeiou]
Match any character that is NOT one of the characters aeiou

Greedy and Lazy

a.*b
The longest string starting with a and ending with b
a.*?b
The shortest string starting with a and ending with b
*?
Repeat any number of times, but as few as possible
+?
Repeat one or more times, but as few as possible
??
Repeat zero or one time, but as few as possible
{n,m}?
Repeat at least n, but no more than m times, but as few as possible
{n,}?
Repeat at least n times, but as few as possible

Alternatives

exp1|exp2
Match exp1 or exp2
\d{10}|\d{3}-\d{3}-\d{4}
Match phone number with or without hyphen

Grouping

(exp)
Match exp and capture it in an automatically numbered group
(?<name>exp)
Match exp and capture it in a group named name
(?:exp)
Match exp, but do not capture it

Positive Lookaround

(?=exp)
Match any position preceding a suffix exp
(?<=exp)
Match any position following a prefix exp
(?<=<(\w+)>).*(?=<\/\1>)
Text between HTML tags

Negative Lookaround

(?!exp)
Match any position after which the suffix exp is not found
(?<!exp)
Match any position before which the prefix exp is not found

Other

\a
Bell character
\b
Normally a word boundary, but within a character class it means backspace
\t
Tab
\r
Carriage return
\v
Vertical tab
\f
Form feed
\n
New line
\e
Escape
\nnn
Character whose ASCII octal code is nnn
\xnn
Character whose hexadecimal code is nn
\unnnn
Character whose Unicode is nnnn
\cN
Control N character, for example carriage return (Ctrl-M) is \cM
\A
Beginning of a string (like ^ but does not depend on the multiline option)
\Z
End of string or before \n at end of string (ignores multiline)
\z
End of string (ignores multiline)
\G
Beginning of the current search

Reference websites