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
Processing...

Test String

Code Generator

Language

Generated Code

$re = '/\A(what[\W_]+is[\W_]+your[\W_]+name[\W_]*){10,}/'; $str = 'First off, sorry for not reviewing quickly. I put off doing so a bit when I first saw this, then ended up quite tired and went to sleep. This seems quite similar in intent to the existing rule "repeating words in {}". Are there cases where that rule and this rule will both match the same text? It looks like you found and fixed the first issue I had, which was the redundant detection name. And fixed the second issue (that post bodies start with an HTML tag). Just FYI: a `<p>` is not the only HTML tag which can start a post body, but it is, by far, the most common. ##### In the version as of the point you removed it from SD: you use `(.+?)` in the second regex. That seems over-broad. I\'d be much more comfortable if there was a relatively/moderately short limit to the number of characters there. Perhaps a couple/few hundred characters? However, that\'s probably not all that critical. The code: ``` repeats = regex.match(r"\\A(\\w+(?:\\W+\\w+){%i}\\W*){10,}" % (len(period.groups(0)[0].split()) + 1), s) ``` doesn\'t appear to do what you\'re intending. It doesn\'t end up looking for a repeating pattern, it just looks for a bunch of words, which would match nearly anything and return the last portion of the text. For example, on [this post](https://metasmoke.erwaysoftware.com/post/366947), the first regex does [this](https://regex101.com/r/tTnkxh/1), which then results in the second regex being `\\Awhat\\W+is\\W+your\\W+(.+?)what\\W+is\\W+your\\b` and is doing [this](https://regex101.com/r/0oVnFf/1). That makes the final regex be `\\A(\\w+(?:\\W+\\w+){2}\\W*){10,}`, which is doing [this on that text](https://regex101.com/r/RI5ePw/1). However, it\'s going to match anything. For example, using the text of this comment as the body text, it does [this]().'; preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0); // Print the entire match result var_dump($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