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

/
/
gsix

Test String

Code Generator

Language

Generated Code

$re = '/\n\s*restart\)(?:(?:(?![#"]|;;).)|\#[^\n]*\n|"[^"]*?")*?\K(haproxy_check_[0-9]+)/six'; $str = 'case "$1" in start) # haproxy_check_01 ;; haproxy_check_02 # haproxy_check_03 rc_status -v # haproxy_check_04 echo " haproxy_check_05 " ;; stop) # haproxy_check_11 haproxy_check_12 # haproxy_check_13 rc_status -v # haproxy_check_14 echo " haproxy_check_15 " ;; try-restart|condrestart) # haproxy_check_21 haproxy_check_22 # haproxy_check_23 rc_status -v # haproxy_check_24 echo " haproxy_check_25 " ;; restart) # haproxy_check_31 haproxy_check_32 # haproxy_check_33 rc_status -v # haproxy_check_34 echo " haproxy_check_35 " ;; check) # haproxy_check_41 haproxy_check_42 # haproxy_check_43 rc_status -v # haproxy_check_44 echo " haproxy_check_45 " ;; reload|force-reload) # haproxy_check_51 haproxy_check_52 # haproxy_check_53 rc_status -v # haproxy_check_54 echo " haproxy_check_55 " ;; status) # haproxy_check_61 haproxy_check_62 # haproxy_check_63 rc_status -v # haproxy_check_64 echo " haproxy_check_65 " ;; probe) # haproxy_check_71 haproxy_check_72 # haproxy_check_73 rc_status -v # haproxy_check_74 echo " haproxy_check_75 " ;; *) # haproxy_check_81 haproxy_check_82 # haproxy_check_83 rc_status -v # haproxy_check_84 echo " haproxy_check_85 " ;; esac'; preg_match_all($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