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Regex Quick Reference

4.53/5 (14 votes)
25 Jun 2013CPOL1 min read 33.7K  
A convenient Regex overview.

Characters - single character of a certain type

\w

word character

\W

non-word character

\d

digit

\D

non-digit

\s

whitespace

\S

non-whitespace

\r

carriage return

\n

line feed

\t

tab

[\b]

backspace

\x00[1]

character by hex value

 

 

Quantifiers - specify number of times to match

?

zero or one

{n[2]}

n times

*

zero or more

{n[3],}

n or more times

+

one or more

{n[4], m}

n to m times

Ranges - specify a range of accepted values

[ abc ]

a,b, or c

[^ abc ]

not a,b, or c

[a-c]

a, c, or anything in between

a|c

either a or c

Anchors - specify a certain position to match

\b

word boundary

\B

not word boundary

\<

start of word

\>

end of word

^

start of line

$

end of line

Assertions - match a pattern without consuming

(?=pat[5])

positive look-ahead

(?!pat)

negative look-ahead

(?<=pat)

positive look-behind

(?<!pat)

negative look-behind

Groups - multiple characters grouped together

(pat)

group with back-reference

(?<name>pat)

group with named back-reference

\n[6]

refer to a back-referenced group

(?:pat)

group without back-reference

Modifiers - specify how the regex engine searches

(?i:pat)

case insensitive

(?-i:pat)

case sensitive

(?s:pat)

dot matches newline

(?-s:pat)

dot does not match newline

(?x:pat)

ignore pattern spacing

Index

  • [1] a specific character’s hexadecimal value
  • [2] an integer greater than 0
  • [3] an integer greater than or equal to 0
  • [4] an integer greater than or equal to 0
  • [5] a RegEx pattern
  • [6] the index of a group in a RegEx pattern
  • [7] the index of a group in a RegEx pattern

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)