Regular Expression ​

strong

Summary of Metacharacters in Regular Expression

Metacharacter

Description

/

Begins and ends the regular expression

.

Matches any single character except the newline

element*

Matches element zero or more times

element+

Matches element one or more times

element?

Matches element zero or one time

[characters]

Matches a character out of those contained within the brackets

[^characters]

Matches a single character that is not contained within the brackets

(regex)

Treats the regex as a group for counting or a following *, +, or ?

left|right

Matches either left or right

[l-r]

Matches a range of characters between l and r

^

Requires match to be at the string's start

$

Requires match to be at the string's end

\b

Matches a word boundary

\B

Matches where there is not a word boundary

\d

Matches a single digit

\D

Matches a single nondigit

\n

Matches a newline character

\s

Matches a whitespace character

\S

Matches a nonwhitespace character

\t

Matches a tab character

\w

Matches a word character (a-z, A-Z, 0-9, and _)

\W

Matches a nonword character (anything but a-z, A-Z, 0-9, and _)

\x

x (useful if x is a metacharacter, but you really want x)

{n}

Matches exactly n times

{n,}

Matches n times or more

{min,max}

Matches at least min and at most max times