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
No Match

/
/
gm

Test String

Code Generator

Language

Generated Code

$re = '/<\/?\s*\b(?(?=a)a(?:bbr|cronym|ddress|pplet|r(?:ea|ticle)|side|udio)?|(?(?=b)b(?:ase|asefont|d[io]|ig|lockquote|ody|r|utton)?|(?(?=c)c(?:anvas|aption|enter|ite|ode|ol(?:group)?)|(?(?=d)d(?:ata(?:list)?|[dlt]|el|etails|fn|ialog|i[rv])|(?(?=e)em(?:bed)?|(?(?=f)f(?:i(?:eldset|g(?:caption|ure))|o(?:nt|oter|rm)|rame(?:set)?)|(?(?=h)h(?:[1-6r]|ead(?:er)?|tml)|(?(?=i)i(?:frame|mg|nput|ns)?|(?(?=k)kbd|(?(?=l)l(?:abel|egend|i(?:nk)?)|(?(?=m)m(?:a(?:in|p|rk)|et(?:a|er))|(?(?=n)n(?:av|o(?:frames|script))|(?(?=o)o(?:bject|l|pt(?:group|ion)|utput)|(?(?=p)p(?:aram|icture|re|rogress)?|(?(?=q)q|(?(?=r)r[pt]|(?(?=r)ruby|(?(?=s)s|(?(?=s)s(?:amp|ection|elect|mall|ource|pan|trike|trong|tyle|ub|ummary|up|vg)|(?(?=t)t(?:able|body|[dhrt]|emplate|extarea|foot|head|ime|itle|rack)|(?(?=u)ul?|(?(?=v)v(?:ar|ideo)|wbr))))))))))))))))))))))\b/m'; $str = ''; preg_match_all($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