Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression

/
/
gmx

Test String

Code Generator

Generated Code

const regex = /(?m) ^ (?= (?: (?: (?(1) (?!) ) ( . ) # (1) | (?(2) (?!) ) (?! \1 ) ( . ) # (2) | (?(3) (?!) ) (?! \1 | \2 ) ( . ) # (3) | (?(4) (?!) ) (?! \1 | \2 | \3 ) ( . ) # (4) | (?(5) (?!) ) (?! \1 | \2 | \3 | \4 ) ( . ) # (5) | (?(6) (?!) ) (?! \1 | \2 | \3 | \4 | \5 ) ( . ) # (6) | (?(7) (?!) ) (?! \1 | \2 | \3 | \4 | \5 | \6 ) ( . ) # (7) | (?(8) (?!) ) (?! \1 | \2 | \3 | \4 | \5 | \6 | \7 ) ( . ) # (8) | (?(9) (?!) ) (?! \1 | \2 | \3 | \4 | \5 | \6 | \7 | \8 ) ( . ) # (9) ) \S*? ){1,9} $ ) (?= (?: \1|\2|\3|\4|\5|\6|\7|\8|\9 )* $ ) (?(DEFINE) (?<one> # (8) (?: (?! \1 ) . )* \1 ) (?<two> # (9) (?: (?! \2 ) . )* \2 ) (?<three> # (10) (?: (?! \3 ) . )* \3 ) (?<four> # (11) (?: (?! \4 ) . )* \4 ) (?<five> # (12) (?: (?! \5 ) . )* \5 ) (?<six> # (13) (?: (?! \6 ) . )* \6 ) (?<seven> # (14) (?: (?! \7 ) . )* \7 ) (?<eight> # (15) (?: (?! \8 ) . )* \8 ) (?<nine> # (16) (?: (?! \9 ) . )* \9 ) ) (?: ### Times Table 9 x 9 = 81 max char string # 1 (?(1) (?= (?&one) {1} (?! .* \1 )) (?(2) (?= (?&two) {1} (?! .* \2 )) (?(3) (?= (?&three){1} (?! .* \3 )) (?(4) (?= (?&four) {1} (?! .* \4 )) (?(5) (?= (?&five) {1} (?! .* \5 )) (?(6) (?= (?&six) {1} (?! .* \6 )) (?(7) (?= (?&seven){1} (?! .* \7 )) (?(8) (?= (?&eight){1} (?! .* \8 )) (?(9) (?= (?&nine) {1} (?! .* \9 )) ))))))))) | # 2 (?(1) (?= (?&one) {2} (?! .* \1 )) (?(2) (?= (?&two) {2} (?! .* \2 )) (?(3) (?= (?&three){2} (?! .* \3 )) (?(4) (?= (?&four) {2} (?! .* \4 )) (?(5) (?= (?&five) {2} (?! .* \5 )) (?(6) (?= (?&six) {2} (?! .* \6 )) (?(7) (?= (?&seven){2} (?! .* \7 )) (?(8) (?= (?&eight){2} (?! .* \8 )) (?(9) (?= (?&nine) {2} (?! .* \9 )) ))))))))) | # 3 (?(1) (?= (?&one) {3} (?! .* \1 )) (?(2) (?= (?&two) {3} (?! .* \2 )) (?(3) (?= (?&three){3} (?! .* \3 )) (?(4) (?= (?&four) {3} (?! .* \4 )) (?(5) (?= (?&five) {3} (?! .* \5 )) (?(6) (?= (?&six) {3} (?! .* \6 )) (?(7) (?= (?&seven){3} (?! .* \7 )) (?(8) (?= (?&eight){3} (?! .* \8 )) (?(9) (?= (?&nine) {3} (?! .* \9 )) ))))))))) | # 4 (?(1) (?= (?&one) {4} (?! .* \1 )) (?(2) (?= (?&two) {4} (?! .* \2 )) (?(3) (?= (?&three){4} (?! .* \3 )) (?(4) (?= (?&four) {4} (?! .* \4 )) (?(5) (?= (?&five) {4} (?! .* \5 )) (?(6) (?= (?&six) {4} (?! .* \6 )) (?(7) (?= (?&seven){4} (?! .* \7 )) (?(8) (?= (?&eight){4} (?! .* \8 )) (?(9) (?= (?&nine) {4} (?! .* \9 )) ))))))))) | # 5 (?(1) (?= (?&one) {5} (?! .* \1 )) (?(2) (?= (?&two) {5} (?! .* \2 )) (?(3) (?= (?&three){5} (?! .* \3 )) (?(4) (?= (?&four) {5} (?! .* \4 )) (?(5) (?= (?&five) {5} (?! .* \5 )) (?(6) (?= (?&six) {5} (?! .* \6 )) (?(7) (?= (?&seven){5} (?! .* \7 )) (?(8) (?= (?&eight){5} (?! .* \8 )) (?(9) (?= (?&nine) {5} (?! .* \9 )) ))))))))) | # 6 (?(1) (?= (?&one) {6} (?! .* \1 )) (?(2) (?= (?&two) {6} (?! .* \2 )) (?(3) (?= (?&three){6} (?! .* \3 )) (?(4) (?= (?&four) {6} (?! .* \4 )) (?(5) (?= (?&five) {6} (?! .* \5 )) (?(6) (?= (?&six) {6} (?! .* \6 )) (?(7) (?= (?&seven){6} (?! .* \7 )) (?(8) (?= (?&eight){6} (?! .* \8 )) (?(9) (?= (?&nine) {6} (?! .* \9 )) ))))))))) | # 7 (?(1) (?= (?&one) {7} (?! .* \1 )) (?(2) (?= (?&two) {7} (?! .* \2 )) (?(3) (?= (?&three){7} (?! .* \3 )) (?(4) (?= (?&four) {7} (?! .* \4 )) (?(5) (?= (?&five) {7} (?! .* \5 )) (?(6) (?= (?&six) {7} (?! .* \6 )) (?(7) (?= (?&seven){7} (?! .* \7 )) (?(8) (?= (?&eight){7} (?! .* \8 )) (?(9) (?= (?&nine) {7} (?! .* \9 )) ))))))))) | # 8 (?(1) (?= (?&one) {8} (?! .* \1 )) (?(2) (?= (?&two) {8} (?! .* \2 )) (?(3) (?= (?&three){8} (?! .* \3 )) (?(4) (?= (?&four) {8} (?! .* \4 )) (?(5) (?= (?&five) {8} (?! .* \5 )) (?(6) (?= (?&six) {8} (?! .* \6 )) (?(7) (?= (?&seven){8} (?! .* \7 )) (?(8) (?= (?&eight){8} (?! .* \8 )) (?(9) (?= (?&nine) {8} (?! .* \9 )) ))))))))) | # 9 (?(1) (?= (?&one) {9} (?! .* \1 )) (?(2) (?= (?&two) {9} (?! .* \2 )) (?(3) (?= (?&three){9} (?! .* \3 )) (?(4) (?= (?&four) {9} (?! .* \4 )) (?(5) (?= (?&five) {9} (?! .* \5 )) (?(6) (?= (?&six) {9} (?! .* \6 )) (?(7) (?= (?&seven){9} (?! .* \7 )) (?(8) (?= (?&eight){9} (?! .* \8 )) (?(9) (?= (?&nine) {9} (?! .* \9 )) ))))))))) ) .*/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?m) ^ (?= (?: (?: (?(1) (?!) ) ( . ) # (1) | (?(2) (?!) ) (?! \\1 ) ( . ) # (2) | (?(3) (?!) ) (?! \\1 | \\2 ) ( . ) # (3) | (?(4) (?!) ) (?! \\1 | \\2 | \\3 ) ( . ) # (4) | (?(5) (?!) ) (?! \\1 | \\2 | \\3 | \\4 ) ( . ) # (5) | (?(6) (?!) ) (?! \\1 | \\2 | \\3 | \\4 | \\5 ) ( . ) # (6) | (?(7) (?!) ) (?! \\1 | \\2 | \\3 | \\4 | \\5 | \\6 ) ( . ) # (7) | (?(8) (?!) ) (?! \\1 | \\2 | \\3 | \\4 | \\5 | \\6 | \\7 ) ( . ) # (8) | (?(9) (?!) ) (?! \\1 | \\2 | \\3 | \\4 | \\5 | \\6 | \\7 | \\8 ) ( . ) # (9) ) \\S*? ){1,9} $ ) (?= (?: \\1|\\2|\\3|\\4|\\5|\\6|\\7|\\8|\\9 )* $ ) (?(DEFINE) (?<one> # (8) (?: (?! \\1 ) . )* \\1 ) (?<two> # (9) (?: (?! \\2 ) . )* \\2 ) (?<three> # (10) (?: (?! \\3 ) . )* \\3 ) (?<four> # (11) (?: (?! \\4 ) . )* \\4 ) (?<five> # (12) (?: (?! \\5 ) . )* \\5 ) (?<six> # (13) (?: (?! \\6 ) . )* \\6 ) (?<seven> # (14) (?: (?! \\7 ) . )* \\7 ) (?<eight> # (15) (?: (?! \\8 ) . )* \\8 ) (?<nine> # (16) (?: (?! \\9 ) . )* \\9 ) ) (?: ### Times Table 9 x 9 = 81 max char string # 1 (?(1) (?= (?&one) {1} (?! .* \\1 )) (?(2) (?= (?&two) {1} (?! .* \\2 )) (?(3) (?= (?&three){1} (?! .* \\3 )) (?(4) (?= (?&four) {1} (?! .* \\4 )) (?(5) (?= (?&five) {1} (?! .* \\5 )) (?(6) (?= (?&six) {1} (?! .* \\6 )) (?(7) (?= (?&seven){1} (?! .* \\7 )) (?(8) (?= (?&eight){1} (?! .* \\8 )) (?(9) (?= (?&nine) {1} (?! .* \\9 )) ))))))))) | # 2 (?(1) (?= (?&one) {2} (?! .* \\1 )) (?(2) (?= (?&two) {2} (?! .* \\2 )) (?(3) (?= (?&three){2} (?! .* \\3 )) (?(4) (?= (?&four) {2} (?! .* \\4 )) (?(5) (?= (?&five) {2} (?! .* \\5 )) (?(6) (?= (?&six) {2} (?! .* \\6 )) (?(7) (?= (?&seven){2} (?! .* \\7 )) (?(8) (?= (?&eight){2} (?! .* \\8 )) (?(9) (?= (?&nine) {2} (?! .* \\9 )) ))))))))) | # 3 (?(1) (?= (?&one) {3} (?! .* \\1 )) (?(2) (?= (?&two) {3} (?! .* \\2 )) (?(3) (?= (?&three){3} (?! .* \\3 )) (?(4) (?= (?&four) {3} (?! .* \\4 )) (?(5) (?= (?&five) {3} (?! .* \\5 )) (?(6) (?= (?&six) {3} (?! .* \\6 )) (?(7) (?= (?&seven){3} (?! .* \\7 )) (?(8) (?= (?&eight){3} (?! .* \\8 )) (?(9) (?= (?&nine) {3} (?! .* \\9 )) ))))))))) | # 4 (?(1) (?= (?&one) {4} (?! .* \\1 )) (?(2) (?= (?&two) {4} (?! .* \\2 )) (?(3) (?= (?&three){4} (?! .* \\3 )) (?(4) (?= (?&four) {4} (?! .* \\4 )) (?(5) (?= (?&five) {4} (?! .* \\5 )) (?(6) (?= (?&six) {4} (?! .* \\6 )) (?(7) (?= (?&seven){4} (?! .* \\7 )) (?(8) (?= (?&eight){4} (?! .* \\8 )) (?(9) (?= (?&nine) {4} (?! .* \\9 )) ))))))))) | # 5 (?(1) (?= (?&one) {5} (?! .* \\1 )) (?(2) (?= (?&two) {5} (?! .* \\2 )) (?(3) (?= (?&three){5} (?! .* \\3 )) (?(4) (?= (?&four) {5} (?! .* \\4 )) (?(5) (?= (?&five) {5} (?! .* \\5 )) (?(6) (?= (?&six) {5} (?! .* \\6 )) (?(7) (?= (?&seven){5} (?! .* \\7 )) (?(8) (?= (?&eight){5} (?! .* \\8 )) (?(9) (?= (?&nine) {5} (?! .* \\9 )) ))))))))) | # 6 (?(1) (?= (?&one) {6} (?! .* \\1 )) (?(2) (?= (?&two) {6} (?! .* \\2 )) (?(3) (?= (?&three){6} (?! .* \\3 )) (?(4) (?= (?&four) {6} (?! .* \\4 )) (?(5) (?= (?&five) {6} (?! .* \\5 )) (?(6) (?= (?&six) {6} (?! .* \\6 )) (?(7) (?= (?&seven){6} (?! .* \\7 )) (?(8) (?= (?&eight){6} (?! .* \\8 )) (?(9) (?= (?&nine) {6} (?! .* \\9 )) ))))))))) | # 7 (?(1) (?= (?&one) {7} (?! .* \\1 )) (?(2) (?= (?&two) {7} (?! .* \\2 )) (?(3) (?= (?&three){7} (?! .* \\3 )) (?(4) (?= (?&four) {7} (?! .* \\4 )) (?(5) (?= (?&five) {7} (?! .* \\5 )) (?(6) (?= (?&six) {7} (?! .* \\6 )) (?(7) (?= (?&seven){7} (?! .* \\7 )) (?(8) (?= (?&eight){7} (?! .* \\8 )) (?(9) (?= (?&nine) {7} (?! .* \\9 )) ))))))))) | # 8 (?(1) (?= (?&one) {8} (?! .* \\1 )) (?(2) (?= (?&two) {8} (?! .* \\2 )) (?(3) (?= (?&three){8} (?! .* \\3 )) (?(4) (?= (?&four) {8} (?! .* \\4 )) (?(5) (?= (?&five) {8} (?! .* \\5 )) (?(6) (?= (?&six) {8} (?! .* \\6 )) (?(7) (?= (?&seven){8} (?! .* \\7 )) (?(8) (?= (?&eight){8} (?! .* \\8 )) (?(9) (?= (?&nine) {8} (?! .* \\9 )) ))))))))) | # 9 (?(1) (?= (?&one) {9} (?! .* \\1 )) (?(2) (?= (?&two) {9} (?! .* \\2 )) (?(3) (?= (?&three){9} (?! .* \\3 )) (?(4) (?= (?&four) {9} (?! .* \\4 )) (?(5) (?= (?&five) {9} (?! .* \\5 )) (?(6) (?= (?&six) {9} (?! .* \\6 )) (?(7) (?= (?&seven){9} (?! .* \\7 )) (?(8) (?= (?&eight){9} (?! .* \\8 )) (?(9) (?= (?&nine) {9} (?! .* \\9 )) ))))))))) ) .*', 'gm') const str = `------------------------------ match_words = ------------------------------ arraigning nonordered abadbacdcacbdbdc mesosome ananna unendued tromometer caucasus intestines i deed horseshoer happenchance reappear deeded pullup arraigning testes mononymy scintillescent couscous ------------------------------ not_match_words = ------------------------------ edified unreverberating underpass interinsert pilfered nippiness gregarinian deicide nonaristocratic rototiller ozonizing museums backbreaker interradiated antistalling naturalize equitriangular reparticipate ppd miasmas cabbage `; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions