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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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
No Match

/
/
gm

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

const regex = /(\d+)(?:[.: ](\d\d))*\s*([aApP][.: ]?[mM][.: ]?|o['’]clock)*\s*(?:A(?:C(?:WS|[DS])?T|DT|E[DS]?T|FT|K[DS]T|LMT|M[S]?T|NAS?T|QTT|RT|ST|W[DS]T|Z(?:OS|[OS])?T|oE|T)|B(?:RS|[NORST])T|C(?:AS|ES|H(?:A[DS]|OS|[OU])|ID?S|LS|hS|[ACDEKLOSVX])?T|D(?:AV|DU)T|E(?:ASS?|ES|GS|[ACDEGS])?T|F(?:JS|KS|[EJKN])T|G(?:A[LM]|IL|[EFMSY])T|H(?:OVS?|[DKS])T|I(?:R(?:KS|[DKS])|[CDOS])T|JST|K(?:OS|RAS?|UY|[GS])T|L(?:H[DS]|IN)T|M(?:A(?:GS|[GRW])T|DT|HT|MT|S[DKT]|UT|VT|YT|T)|N(?:FD|OVS?|Z[DS]|[CDFPRSU])T|O(?:MSS?|RA)T|P(?:ETS?|HO|M[DS]|ON|YS|[DEGHKSWY])?T|QYZT|R(?:OT|E)T|S(?:A[KMS]|RE|YO|[BCGRS])T|T(?:AH|OS|[FJKLMORV])T|U(?:LAS?T|TC|YS?T|ZT)|V(?:LAS?|OS|[EU])T|W(?:A(?:RS|[KS])?T|ES?T|FT|GS?T|I(?:TA|[BT])|ST|T)|Y(?:A(?:KS|[KP])|EKS?)T|[ABCDEFGHIKLMNOPQRSTUVWXYZ])/gm; // Alternative syntax using RegExp constructor // const regex = new RegExp('(\\d+)(?:[.: ](\\d\\d))*\\s*([aApP][.: ]?[mM][.: ]?|o[\'’]clock)*\\s*(?:A(?:C(?:WS|[DS])?T|DT|E[DS]?T|FT|K[DS]T|LMT|M[S]?T|NAS?T|QTT|RT|ST|W[DS]T|Z(?:OS|[OS])?T|oE|T)|B(?:RS|[NORST])T|C(?:AS|ES|H(?:A[DS]|OS|[OU])|ID?S|LS|hS|[ACDEKLOSVX])?T|D(?:AV|DU)T|E(?:ASS?|ES|GS|[ACDEGS])?T|F(?:JS|KS|[EJKN])T|G(?:A[LM]|IL|[EFMSY])T|H(?:OVS?|[DKS])T|I(?:R(?:KS|[DKS])|[CDOS])T|JST|K(?:OS|RAS?|UY|[GS])T|L(?:H[DS]|IN)T|M(?:A(?:GS|[GRW])T|DT|HT|MT|S[DKT]|UT|VT|YT|T)|N(?:FD|OVS?|Z[DS]|[CDFPRSU])T|O(?:MSS?|RA)T|P(?:ETS?|HO|M[DS]|ON|YS|[DEGHKSWY])?T|QYZT|R(?:OT|E)T|S(?:A[KMS]|RE|YO|[BCGRS])T|T(?:AH|OS|[FJKLMORV])T|U(?:LAS?T|TC|YS?T|ZT)|V(?:LAS?|OS|[EU])T|W(?:A(?:RS|[KS])?T|ES?T|FT|GS?T|I(?:TA|[BT])|ST|T)|Y(?:A(?:KS|[KP])|EKS?)T|[ABCDEFGHIKLMNOPQRSTUVWXYZ])', 'gm') const str = `12:34 AM ACDT`; const subst = `$1`; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

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