Character Classes

LAST UPDATED: DECEMBER 22, 2025

A character class, expressed by characters enclosed in [], allows multiple possible characters at a specific position in a pattern. A pattern can contain multiple character classes, each matching a single character in the input text.

Literal Characters

Any single character listed inside the [] can match an input character, at the corresponding position.

Examples - Literal Characters

EXAMPLE 1

Input:

CODE

{{ "D3" | regex_match("[ABCD]") }}
{{ "D3" | regex_match("[abcd]") }}

Return Data:

CODE

True
False

EXAMPLE 2

Input:

CODE

{{ "D3" | regex_match("d[1234]") }}
{{ "D3" | regex_match("d[5678]") }}
{{ "D3" | regex_match("D[1234]") }}
{{ "D3" | regex_match("D[5678]") }}

Return Data:

CODE

False
False
True
False

EXAMPLE 3

Input:

CODE

{{ "click here" | regex_match("[ ]") }}
{{ "click here" | regex_match("[ ]") }}

Explanation: In the first input, the character between "click" and "here" is U+2006 SIX-PER-EM SPACE, not the ASCII space character (U+0020).

Return Data:

CODE

False
True

EXAMPLE 4

Input:

CODE

{{ "𝗌ecure" | regex_match("[𝗌]") }}  
{{ "securе" | regex_match("[𝗌]") }}

Explanation: [𝗌] matches the mathematical sans-serif small 𝗌 (U+1D5CC).

Return Data:

CODE

True
False

EXAMPLE 5

Input:

CODE

{{ "docuмent.exe" | regex_match("docu[м]ent") }}  
{{ "document.exe" | regex_match("docu[м]ent") }}

Explanation: [м] matches the Cyrillic character м (U+043C).

Return Data:

CODE

True
False

EXAMPLE 6

Input:

CODE

{{ "Google" | regex_match("[ѻ]") }}
{{ "Gѻѻgle" | regex_match("[ѻ]") }}

Explanation: [ѻ] matches the literal Cyrillic character ѻ (U+047B).

Return Data:

CODE

False
True

EXAMPLE 7

Input:

CODE

{{ "ａpple.com" | regex_match("[ａ]pple") }}  
{{ "apple.com" | regex_match("[ａ]pple") }}

Explanation: [ａ] matches the fullwidth character ａ (U+FF41).

Return Data:

CODE

True
False

EXAMPLE 8

Input:

CODE

{{ "cmd.exe /c whoami & net user Ryan /add" | regex_match("[&]") }}

Return Data:

CODE

True

Ranges

A contiguous sequence of characters (i.e., range) is expressed using a - in the format [start-end]. Multiple ranges may be included within the same []. The ranges within a [] matches exactly one character whose Unicode code point falls within the specified bounds, inclusive. Ranges may be combined with literal characters, which can appear before, between, or after ranges.

Sample Range Types

SEMANTIC NOTE

Ranges are based on the underlying integer character code.

ASCII letter ranges are contiguous and correspond exactly to the English alphabet.
Non-ASCII ranges can include non-letter characters that fall between the endpoints.

ASCII Lowercase Ranges *

EXAMPLES

Entire alphabet: [a-z]
Subranges: [a-g], [m-r], [u-z]
Unioned subranges: [a-fm-s], [a-cx-z], [a-dh-kp-v]

ASCII Uppercase Ranges *

EXAMPLES

Entire alphabet: [A-Z]
Subranges: [A-G], [M-R], [U-Z]
Unioned subranges: [A-FM-S], [A-CX-Z], [A-DH-KP-V]

ASCII Digit Ranges *

EXAMPLES

All digits: [0-9]
Subranges: [0-3], [4-7], [7-9]
Unioned subranges: [0-35-7], [1-26-8], [0-47-9]

ASCII Mixed Ranges *

EXAMPLES

Uppercase + lowercase: [A-Za-z]
Shorter combined spans: [A-Ga-g], [M-Rm-r], [U-Zu-z]
Multiple combined spans: [A-FM-Sa-fm-s], [A-CX-Za-cx-z], [A-DH-KP-Va-dh-kp-v]

Latin Lowercase Ranges *

EXAMPLES

Full code-point range: [a-ž]
Subranges: [á-ř], [č-ň], [š-ž]
Unioned subranges: [a-řu-ž], [á-čě-ň], [č-ťž]

Latin Uppercase Ranges *

EXAMPLES

Full code-point range: [A-Ž]
Subranges: [Á-Ř], [Č-Ň], [Š-Ž]
Unioned subranges: [A-ŘU-Ž], [Á-ČĚ-Ň], [Č-ŤŽ]

Latin Mixed Ranges *

EXAMPLES

Uppercase + lowercase: [A-Ža-ž]
Shorter combined spans: [Á-Řá-ř], [Č-Ňč-ň], [Š-Žš-ž]
Multiple combined spans: [A-Řa-řU-Žu-ž], [Á-Čá-čĚ-Ňě-ň], [Č-Ťč-ťŠ-Žš]

Cyrillic Lowercase Ranges *

EXAMPLES

Full code-point range: [а-я]
Subranges: [д-п], [р-ч], [ж-н]
Unioned subranges: [а-ео-я], [д-йл-н], [ж-пт-я]

Cyrillic Uppercase Ranges *

EXAMPLES

Full code-point range: [А-Я]
Subranges: [Д-П], [Р-Ч], [Ж-Н]
Unioned subranges: [А-ЕО-Я], [Д-ЙЛ-Н], [Ж-ПТ-Я]

Cyrillic Mixed Ranges *

EXAMPLES

Uppercase + lowercase: [А-Яа-я]
Shorter combined spans: [Д-Пд-п], [Р-Чр-ч], [Ж-Нж-н]
Multiple combined spans: [А-Еа-еО-Яо-я], [Д-Йд-йЛ-Нл-н], [Ж-Пж-пТ-Ят-я]

Devanagari Letter Ranges *

EXAMPLES

Full code-point range: [ऀ-ॿ]
Subranges: [अ-औ], [क-ह], [ट-न], [प-य], [र-ळ]
Unioned subranges: [अ-औक-ह], [क-गत-न], [ट-नप-भ], [अ-इक-गप-भ]

Devanagari Consonant Ranges *

EXAMPLES

Primary consonants: [क-ह]
Subranges: [क-च], [ट-थ], [प-भ]
Unioned subranges: [क-घट-थ], [क-छप-भ], [ट-नय-ळ]

Devanagari Vowel Ranges *

EXAMPLES

Independent vowels: [अ-औ]
Subranges: [अ-ऊ], [ए-औ]
Unioned subranges: [अ-इए-ओ], [अ-ऊए-ऐ]
Dependent vowel signs: [ा-ौ]
Subranges: [ा-ी], [े-ै]
Unioned subranges: [ा-ीे-ै]

Devanagari Digit Ranges *

EXAMPLES

All digits: [०-९]
Subranges: [०-४], [५-७], [७-९]
Unioned subranges: [०-२४-६], [१-३५-९], [०-४७-९]

Devanagari Mixed Ranges *

EXAMPLES

Letters and digits: [अ-औ०-९], [क-ह०-४]
Letters and vowel signs: [क-हा-ी], [अ-औे-ै]
Consonants, vowels, digits: [अ-औक-ह०-९], [क-गअ-इ३-५]
Multiple mixed spans: [अ-इक-घ५-७], [क-घट-न०-३], [अ-औक-ढ०-९]

Chinese Ranges *

EXAMPLES

Full code-point range: [一-龯]
Subranges: [木-林], [河-海], [花-草], [金-銅]
Unioned subranges: [日-月水-火], [山-川田-禾]

Japanese Hiragana Ranges *

EXAMPLES

Full code-point range: [ぁ-ゟ]
Subranges: [か-そ], [た-の], [は-ほ]
Unioned subranges: [ぁ-ゑを-ゟ], [か-しな-の], [た-とま-も]

Japanese Katakana Ranges *

EXAMPLES

Full code-point range: [ァ-ヿ], [ㇰ-ㇿ]
Subranges: [カ-ソ], [タ-ノ], [ハ-ホ], [ㇰ-ㇶ], [ㇷ-ㇿ]
Unioned subranges: [ァ-ヱヲ-ヿ], [カ-セタ-ト], [ナ-ノマ-モ], [ㇰ-ㇲㇴ-ㇿ]

Japanese Mixed Ranges *

EXAMPLES

Hiragana + Katakana: [ぁ-ゟァ-ヿ]
Shorter mixed spans: [か-そカ-ソ], [た-のタ-ノ]
Multiple mixed spans: [ぁ-ゑァ-ヱを-ゟヲ-ヿ]

Korean (Hangul) Ranges *

EXAMPLES

Full code-point range: [가-힣], [ᄀ-ᇿ], [ㄱ-ㆎ]
Subranges: [가-딯], [따-뛳], [라-맇], [ᄀ-ᄋ], [ᄌ-ᄒ], [ㄱ-ㄷ], [ㅂ-ㅅ]
Unioned subranges: [가-나다-랃], [카-킿파-핗], [ᄀ-ᄈᄋ-ᄒ], [ㄱ-ㄴㅁ-ㅂ], [ㅅ-ㅇㅈ-ㅊ]

Arabic Letter Ranges *

EXAMPLES

Full code-point range: [ء-ي]
Subranges: [ا-ه], [ب-خ], [س-ف], [ق-ل], [م-ي]
Unioned subranges: [ا-خب-ذ], [س-قك-م], [ب-حث-ص]

Arabic Digit Ranges *

EXAMPLES

All digits: [٠-٩]
Subranges: [٠-٤], [٥-٧], [٧-٩]
Unioned subranges: [٠-٢٤-٦], [١-٣٥-٩], [٠-٤٧-٩]

Arabic Mixed Ranges *

EXAMPLES

Letters and digits: [ا-ه٠-٩], [م-ي٢-٣]
Letters with internal spans: [ب-حث-ص], [ا-خب-ذ]
Letters + digits: [ب-حث-ص٥-٧]

Greek Lowercase Ranges *

EXAMPLES

Full code-point range: [α-ω]
Subranges: [β-ζ], [η-μ], [ν-σ], [τ-ψ]
Unioned subranges: [α-δε-ζ], [η-θλ-ξ], [ν-σφ-ψ]

Greek Uppercase Ranges *

EXAMPLES

Full code-point range: [Α-Ω]
Subranges: [Β-Ζ], [Η-Μ], [Ν-Σ], [Τ-Φ]
Unioned subranges: [Α-ΔΗ-Κ], [Β-ΘΜ-Ρ], [Ν-ΣΤ-Φ]

Greek Mixed Ranges *

EXAMPLES

Uppercase + lowercase: [Α-Ωα-ω]
Shorter combined spans: [Β-Ζβ-ζ], [Η-Μη-μ], [Ν-Σν-σ]
Unioned combined spans: [Α-Δα-δΗ-Κη-κ], [Β-Θβ-θΜ-Ρμ-ρ]

Hebrew Ranges *

EXAMPLES

Full code-point range: [א-ת]
Subranges: [ב-ח], [ט-ע], [פ-ת]
Unioned subranges: [א-דט-מ], [ב-זפ-צ], [ח-יכ-ס]
Mixed Hebrew spans: [א-תך-ץ], [ב-חך-ם], [ט-פף-ץ]

Examples - Ranges

EXAMPLE 1

Input:

CODE

{{ 'D' | regex_match('[a-z]') }}
{{ '3' | regex_match('[A-Z]') }}
{{ 'Security' | regex_match('S[d-f]curity') }}

Return Data:

CODE

False
False
True

EXAMPLE 2

Input:

CODE

{{ 'D' | regex_match('[0-9a-zA-Z]') }}
{{ '3' | regex_match('[0-9a-zA-Z]') }}
{{ '_' | regex_match('[0-9a-zA-Z]') }}

Return Data:

CODE

True
True
False

EXAMPLE 3

Input:

CODE

{{ '-' | regex_match('[-0-9a-zA-Z]') }}
{{ '!' | regex_match('[0-9!a-zA-Z]') }}
{{ '@' | regex_match('[0-9a-z@A-Z]') }}
{{ '#' | regex_match('[0-9a-zA-Z#]') }}

Return Data:

CODE

True
True
True
True

EXAMPLE 4

Input:

CODE

{{ '192.168.200.8' | regex_match('192\.168\.200\.[0-9][0-9]') }}
{{ '192.168.200.30' | regex_match('192\.168\.200\.[0-9][0-9]') }}
{{ '192.168.200.100' | regex_match('192\.168\.200\.1[0-9][0-9]') }}
{{ '192.168.200.100' | regex_match('192\.168\.200\.1[5-9][5-9]') }}
{{ '192.168.200.188' | regex_match('192\.168\.200\.1[5-9][5-9]') }}

Return Data:

CODE

False
True
True
False
True

EXAMPLE 5

Input:

CODE

{{ 's' | regex_match('[a-řu-ž]') }}
{{ 'д' | regex_match('[а-я]') }}
{{ 'क' | regex_match('[क-ह]') }}
{{ '林' | regex_match('[河-海]') }}
{{ 'た' | regex_match('[か-そ]') }}
{{ '한' | regex_match('[가-힣]') }}
{{ 'ق' | regex_match('[ق-ل]') }}
{{ 'Ж' | regex_match('[Α-Ωα-ω]') }}
{{ 'ך' | regex_match('[א-תך-ץ]') }}

Return Data:

CODE

True
True
True
False
False
True
True
False
True

Negations

Negation is expressed using a ^ immediately after the opening bracket, in the format [^chars], to match any single character not listed in the []. If the ^ appears in any other position, it is treated as a literal character.

Examples - Negations

EXAMPLE 1

Input:

CODE

{{ 'D' | regex_match('[^0-9]') }}
{{ '3' | regex_match('[^0-9]') }}
{{ 'D3' | regex_match('[^0-9]') }}
{{ 'D3' | regex_match('D[^0-9]') }}

Return Data:

CODE

True
False
True
False

EXAMPLE 2

Input:

CODE

{{ '!' | regex_match('[^A-Za-z0-9]') }}
{{ 'D3' | regex_match('D[^A-Za-z0-9]') }}

Return Data:

CODE

True
False

EXAMPLE 3

Input:

CODE

{{ '192.168.1.1' | regex_match('192[^!@#]168') }}
{{ '192.168.1.1' | regex_match('192[^,./]168') }}

Return Data:

CODE

True
False

EXAMPLE 4

Input:

CODE

{{ '^' | regex_match('[^^]') }}
{{ '^' | regex_match('[^]-_]') }}

Return Data:

CODE

False
False

See 005D to 005F.

Shorthand Classes

Shorthand classes are abbreviated forms of longer character class expressions. Each shorthand class has a corresponding negated form.

Digits

\d – Matches a decimal digit from 0 through 9. It is the same as [0-9].

\D – Matches any character that is not a decimal digit from 0 through 9. It is the same as [^0-9].

Examples - Shorthand Digits

EXAMPLE 1

Input:

CODE

{{ '3' | regex_match('\d') }}
{{ 'D' | regex_match('\d') }}

Return Data:

CODE

True
False

EXAMPLE 2

Input:

CODE

{{ 'D' | regex_match('\D') }}
{{ '3' | regex_match('\D') }}

Return Data:

CODE

True
False

EXAMPLE 3

Input:

CODE

{{ 'D3 Security' | regex_match('D\d [Security]') }}
{{ 'D3 Security' | regex_match('D\D [Security]') }}

Return Data:

CODE

True
False

Whitespaces

\s – Matches a whitespace character. It is the same as [ \t\n\r\f\v].

\S – Matches any character that is not whitespace. It is the same as [^ \t\n\r\f\v].

Examples - Shorthand Whitespaces

EXAMPLE 1

Input:

CODE

{{ 'D' | regex_match('\s') }}
{{ '3' | regex_match('\s') }}
{{ ' ' | regex_match('\s') }}
{{ '\t' | regex_match('\s') }}
{{ '\n' | regex_match('\s') }}
{{ '\r' | regex_match('\s') }}
{{ '\f' | regex_match('\s') }}
{{ '\v' | regex_match('\s') }}

Return Data:

CODE

False
False
True
True
True
True
True
True

EXAMPLE 2

Input:

CODE

{{ 'D' | regex_match('\S') }}
{{ '3' | regex_match('\S') }}
{{ ' ' | regex_match('\S') }}
{{ '\t' | regex_match('\S') }}
{{ '\n' | regex_match('\S') }}
{{ '\r' | regex_match('\S') }}
{{ '\f' | regex_match('\S') }}
{{ '\v' | regex_match('\S') }}

Return Data:

CODE

True
True
False
False
False
False
False
False

EXAMPLE 3

Input:

CODE

{{ 'D3 Security' | regex_match('\S\S\s\S\S\S\S\S\S\S') }}

Return Data:

CODE

True

Word Characters

\w – Matches a letter, decimal digit, or underscore. It is the same as [A-Za-z0-9_].

\W – Matches any character that is not a word character. It is the same as [^A-Za-z0-9_].

Examples - Shorthand Words

EXAMPLE 1

Input:

CODE

{{ 'D' | regex_match('\w') }}
{{ 'd' | regex_match('\w') }}
{{ '3' | regex_match('\w') }}
{{ '_' | regex_match('\w') }}
{{ ' ' | regex_match('\w') }}
{{ '!' | regex_match('\w') }}

Return Data:

CODE

True
True
True
True
False
False

EXAMPLE 2

Input:

CODE

{{ 'D' | regex_match('\W') }}
{{ 'd' | regex_match('\W') }}
{{ '3' | regex_match('\W') }}
{{ '_' | regex_match('\W') }}
{{ ' ' | regex_match('\W') }}
{{ '!' | regex_match('\W') }}

Return Data:

CODE

False
False
False
False
True
True

EXAMPLE 3

Input:

CODE

{{ 'D3 Security' | regex_match('\w\w\W\w\w\w\w\w\w\w') }}

Return Data:

CODE

True

Special Cases

Some characters require specific placement or escaping to be treated literally:

] – Must be placed immediately after [, unless escaped.
- – Must be placed at the start or end, unless escaped.
^ – Must not be placed immediately after [, unless escaped.

Examples - Special Cases

EXAMPLE 1

Input:

CODE

{{ ']' | regex_match('[]]') }}
{{ ']' | regex_match('[ ]]') }}
{{ ']' | regex_match('[ \]]') }}

Return Data:

CODE

True
False
True

Explanation: [ ]] matches a characters that is either a space (' '), or a closing square bracket (']').

EXAMPLE 2

Input:

CODE

{{ '-' | regex_match('[-a-z]') }}
{{ '-' | regex_match('[a-z]') }}
{{ '-' | regex_match('[a\-z]') }}
{{ '-' | regex_match('[a-z-]') }}

Return Data:

CODE

True
False
True
True

EXAMPLE 3

Input:

CODE

{{ '^' | regex_match('[\^]') }}
{{ '^' | regex_match('[^^]') }}
{{ '^' | regex_match('[ ^]') }}

Return Data:

CODE

True
False
True

Explanation: In the pattern [^^], the caret (^) appears directly after [, so it negates the character class. The pattern therefore matches any single character except ^.

Troubleshooting

Error: "bad character range <range> at position <#>"

This error message means that the system has detected an invalid range definition inside a character class. Ranges must be ordered from a lower code point to a higher code point.

EXAMPLE 1

Input:

CODE

{{ 'd' | regex_match('[z-a]') }}

Error:

CODE

bad character range z-a at position 1

EXAMPLE 2

Input:

CODE

{{ 'D3' | regex_match('D[9-0]') }}

Error:

CODE

bad character range 9-0 at position 2