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

Substitution

Processing...

Code Generator

Language

Generated Code

$re = '/^(?!(?:\s*$|.*(?:Niveau|stime)))(.*$)([\s\S]*?)(\1\s*)/m'; $str = 'vide vide Time: stime 3:30 PM vide vide NN NN NP stime LS NP NN NN ----------Niveau 1-------------- Time: | 0 | 263.0 | 266.0 | 0,0113 NP | 0 | 0.0 | 24885.0 | 1 3:30 | -0 | 104.0 | 120.0 | 0,1333 LS | -0 | 0.0 | 13134.0 | 1 PM | -1 | 134.0 | 238.0 | 0,437 NP | -1 | 0.0 | 24885.0 | 1 ----------Niveau 2-------------- 3:30 PM | -0 | 30.0 | 41.0 | 0,2683 3:30 NP | -0 | 133.0 | 55.0 | -1,4182 LS PM | -0 | 42.0 | 237.0 | 0,8228 LS NP | -0 | 0.0 | 2456.0 | 1 ----------Niveau 3-------------- vide vide Time: stime 3:30 pm vide vide NN NN NP stime LS NN NN NN ----------Niveau 1-------------- Time: | 0 | 263.0 | 266.0 | 0,0113 NP | 0 | 0.0 | 24885.0 | 1 3:30 | -0 | 104.0 | 120.0 | 0,1333 LS | -0 | 0.0 | 13134.0 | 1 pm | -1 | 38.0 | 54.0 | 0,2963 NN | -1 | 0.0 | 59511.0 | 1 ----------Niveau 2-------------- 3:30 pm | -0 | 9.0 | 9.0 | 0 3:30 NN | -0 | 36.0 | 24.0 | -0,5 LS pm | -0 | 22.0 | 52.0 | 0,5769 LS NN | -0 | 0.0 | 2658.0 | 1 ----------Niveau 3-------------- '; $subst = "\1\2"; $result = preg_replace($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