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

/
/
g

Test String

Code Generator

Generated Code

$re = '/K\'(?P<name1>81|61|64|44|86|678|41|49|33|685|1(?:33|45)?|\d{2,3})\d+/'; $str = 'K\'8134567 K\'81345678 K\'6134516789 K\'61345678 K\'643456 K\'646345678 K\'1234567890 K\'12345678901 K\'1454567890 <<<--- want 145 returned and not 1 K\'13345678901 <<<--- want 133 returned and not 1 K\'3214567890123 K\'32134567890123 K\'3654567890123 K\'8934567890123 K\'6554567890123 I am interested in the digits after K\' I am looking to do this using regex but not sure if it can be done. What I want is: if the number starts with 81 return 81 if the number starts with 61 return 61 ... if the number starts with something i am not interested in return other(or its first digits of 1-3) The above criteria works: but what I also want is: if the fist digit is 1 then return 1 BUT if the fist digit is 1 and the 2nd and 3rd digit are 45 return 145 and don\'t return just 1 if the fist digit is 1 and the 2nd and 3rd digit are 33 return 133 and don\'t return just 1 I presume I have to put something inside this part of the regex |(1)\\d+| Questions: Does regex sort the data first? Is the order of the regex search important to how it is implemented? i deally I do not want this. '; preg_match_all($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