RegExr: Learn, Build, & Test RegEx

Add Test

Build a suite of tests that your expression should (or should not) match.

Create new tests with the 'Add Test' button. Click a test to edit the name, type, & text.

Character classes
.	any character except newline
\w \d \s	word, digit, whitespace
\W \D \S	not word, digit, whitespace
[abc]	any of a, b, or c
[^abc]	not a, b, or c
[a-g]	character between a & g
Anchors
^abc$	start / end of the string
\b \B	word, not-word boundary
Escaped characters
\. \* \\	escaped special characters
\t \n \r	tab, linefeed, carriage return
Groups & Lookaround
(abc)	capture group
\1	backreference to group #1
(?:abc)	non-capturing group
(?=abc)	positive lookahead
(?!abc)	negative lookahead
Quantifiers & Alternation
a* a+ a?	0 or more, 1 or more, 0 or 1
a{5} a{2,}	exactly five, two or more
a{1,3}	between one & three
a+? a{2,}?	match as few as possible
ab\|cd	match ab or cd

Character classes

any character except newline

\w \d \s

word, digit, whitespace

\W \D \S

not word, digit, whitespace

[abc]

any of a, b, or c

[^abc]

not a, b, or c

[a-g]

character between a & g

Anchors

^abc$

start / end of the string

\b \B

word, not-word boundary

Escaped characters

\. \* \\

escaped special characters

\t \n \r

tab, linefeed, carriage return

Groups & Lookaround

(abc)

capture group

backreference to group #1

(?:abc)

non-capturing group

(?=abc)

positive lookahead

(?!abc)

negative lookahead

Quantifiers & Alternation

a* a+ a?

0 or more, 1 or more, 0 or 1

a{5} a{2,}

exactly five, two or more

a{1,3}

between one & three

a+? a{2,}?

match as few as possible

ab|cd

match ab or cd

Expression

Tools

RegEx Engine

Expression Flags