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

/
/
gimx

Test String

Code Generator

Language

Generated Code

$re = '/^ # Uncomment to allow prefix continuation (second letter of a dangling match) # ([abcdefghiklmnoprstuvy\ ])? ( \ |(?: # Single-letter elements [BCFHIKNOPSUVWY] ) |(?: # Two-letter elements. (?:A[cglmrstu])|(?:B[aehikr])|(?:C[adeflmnorsu])|(?:D[bsy]) | (?:E[rsu])|(?:F[elmr])|(?:G[ade])|(?:H[efgos])|(?:I[nr]) | (?:K[r])|(?:L[airuv])|(?:M[cdgnot])|(?:N[abdehiop]) | (?:O[gs])|(?:P[abdmortu])|(?:R[abefghnu])|(?:S[bcegimnr]) | (?:T[abcehilms])|(?:X[e])|(?:Yb)|(?:Z[nr]) ) |(?: # Smushed trigrams. No need to go past trigrams because two twos make four (?:A(?:ga|gd|ge|la|lr|md|mg|mt|ra|re|rg|ta|te|tl|tm)) |(?:E(?:ra|re|rg)) |(?:G(?:ag|al|am|ar|at|er)) |(?:L(?:ag|al|am|ar|at|ra|re|rg)) |(?:M(?:ga|gd|ge|ta|te|tl|tm)) |(?:R(?:ag|al|am|ar|at|er|ga|gd|ge)) |(?:T(?:ag|al|am|ar|at|er|la|lr|md|mg|mt)) |(?:X(?:er)) |(?:Z(?:ra|re|rg)) ) # repeated any number of times )+ # Uncomment to allow last letter if it\'s a potential first letter of the next word # ([ADEGLMRTXZ]\ *)? $/imx'; $str = '**(See bottom for Javascript/one-line version)** If you want continuation -- to look for "fez" "rave" "rites" chains, strike the second and second-to-last lines. Latex needs a suffix and ear needs a prefix. latex ear latexear fez rave rites fezraverites if you don\'t want overlap, comment out the big group with (?<=..) tests. Walter and lag will not match: lag is La + Ag but can\'t be L+Ag or La+G; walter is W+Al+Te+Er but there\'s no single A, L, T, E or R to make it a strict chain of elements. Walter aga McLvinandfezrobHogwartsWizrdsofMoney ## Match: McLvIn McLvinandfezrobHogwartsWizrdsofMoney zr McLvinand ergo Orgasmicallabkitscashflow update Organicfurbies Babkes WalterWhite That ibexesnogladybirds Xenophobic picnicforgus snapes siriusblack ## match until last letter, and last letter potentially starts a new word (allows continuation) fez McLvinandfez bobatea # La + At + Te late # the x awaits an e in the next word latex # N + Nd + Dy + Y + Yb ndyb # the a is a potential continuation andy # ...but the x can\'t be a second letter xndyb ## Don\'t Match at some interior point in line Jemmamead ## Don\'t Match anywhere in line JemmaQmead ### For Javascript: ^([abcdefghiklmnoprstuvy\\s])?(\\ |(?:[BCFHIKNOPSUVWY])|(?:(?:A[cglmrstu])|(?:B[aehikr])|(?:C[adeflmnorsu])|(?:D[bsy])|(?:E[rsu])|(?:F[elmr])|(?:G[ade])|(?:H[efgos])|(?:I[nr])|(?:K[r])|(?:L[airuv])|(?:M[cdgnot])|(?:N[abdehiop])|(?:O[gs])|(?:P[abdmortu])|(?:R[abefghnu])|(?:S[bcegimnr])|(?:T[abcehilms])|(?:X[e])|(?:Yb)|(?:Z[nr]))|(?:(?:A(?:ga|gd|ge|la|lr|md|mg|mt|ra|re|rg|ta|te|tl|tm))|(?:E(?:ra|re|rg))|(?:G(?:ag|al|am|ar|at|er))|(?:L(?:ag|al|am|ar|at|ra|re|rg))|(?:M(?:ga|gd|ge|ta|te|tl|tm))|(?:R(?:ag|al|am|ar|at|er|ga|gd|ge))|(?:T(?:ag|al|am|ar|at|er|la|lr|md|mg|mt))|(?:X(?:er))|(?:Z(?:ra|re|rg))))+([ADEGLMRTXZ]\\ *)?$'; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php