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

/
/
gm

Test String

Substitution

Processing...

Code Generator

Generated Code

$re = '/(?xXmi) (?: (?# use non-capture for details in debugging) (?: (?<match> (?# If quoted value) (?<quot_char>(?<!\\\\)["\']) (?# Quoted content) (?: (?: (?# Match as many characters that aren\'t quotation char) (?# or escape char as possible. ) (?:(?:(?!\k<quot_char>|\\\\)).+) (?: (?# Match any/all escape chars that do not have the) (?# quotation char following it. ) (?:(?:\\\\)*(?!\k<quot_char>))? (?# If there is an escape char followed by the quotation) (?# quotation char match them. ) (?:[\\\\]\k<quot_char>)? )*? ) ) (?<close_quot>\k<quot_char>) | (?# if simple token) (?<basic>[^ \n]+)+ ) ) (?<trail_ws>[ ]+)? )/m'; $str = '-t1a1 -t2a1 -t2a2 -t3a1 -t3a2 -t4a1 Test1value -t4a2 test4a2value -t4a3 t4a3value -t5a1EscQuot \\\'t5a1valueESQ\\\' -t5a2EscQuot \\"t5a2valueEDQ\\" -t6a1 "t6a1value1DQWord1 t6a1value1DQWord1" -t6a2SQuot \'t6a2value1SQWord1 t6a2value1SQWord2 t6a2value1SQWord3 \' -t7a1SQuotEmpty \'\' -t7a2DQuotEmpty "" '; $subst = "\n${match}"; $result = preg_replace($re, $subst, $str); echo "The result of the substitution is ".$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 PHP, please visit: http://php.net/manual/en/ref.pcre.php