Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

Code Generator

Language

Generated Code

$re = '/\b(?:https?:\/\/)(?:www\d?\.)?[-\w\d&#%?\/=\.+]+\b/m'; $str = 'HEN 1 ELSE 0 END AS CONNECT_BY_ISBRANCH , CASE WHEN t.id IN (SELECT parent_id FROM tbl) THEN 0 ELSE 1 END AS CONNECT_BY_ISLEAF , CASE WHEN th.SYS_CONNECT_BY_PATH_id LIKE \'%/\' + CAST(t.id AS VARCHAR(MAX)) + \'/%\' THEN 1 ELSE 0 END AS CONNECT_BY_ISCYCLE , th.SYS_CONNECT_BY_PATH_id + CAST(t.id AS VARCHAR(MAX)) + \'/\' AS SYS_CONNECT_BY_PATH_id , th.SYS_CONNECT_BY_PATH_name + CAST(t.name AS VARCHAR(MAX)) + \'/\' AS SYS_CONNECT_BY_PATH_name , th.root_id , t.* FROM tbl t JOIN tbl_hierarchy th ON (th.id = t.parent_id) -- CONNECT BY PRIOR id = parent_id WHERE th.CONNECT_BY_ISCYCLE = 0) -- NOCYCLE SELECT th.* --, REPLICATE(\' \', (th."LEVEL" - 1) * 3) + th.name AS tbl_hierarchy FROM tbl_hierarchy th JOIN tbl CONNECT_BY_ROOT ON (CONNECT_BY_ROOT.id = th.root_id) ORDER BY th.SYS_CONNECT_BY_PATH_name; -- ORDER SIBLINGS BY name هذا شرح لميزات CONNECT BY الموضّحة أعلاه: https://academy.hsoub.com/programming/sql/%D8%A7%D9%84%D8%AA%D8%B9%D8%A7%D8%A8%D9%8A%D8%B1-%D8%A7%D9%84%D8%AC%D8%AF%D9%88%D9%84%D9%8A%D8%A9-%D8%A7%D9%84%D8%B4%D8%A7%D8%A6%D8%B9%D8%A9-common-table-expressions-%D9%81%D9%8A-sql-r856/ and http://www.watheq.xyz/ and https://twitter.com/home العبارات CONNECT BY: تحدّد العلاقة التي تعرّف التشعّب START WITH: تحدّد العقدة الجذرية (root nodes). ORDER SIBLINGS BY: تحدّد ترتيب النتائج المعاملات NOCYCLE: توقِف معالجة فرع معيّن عند رصد شعبة دورية (loop). لأنّ الشعب الصالحة هي الشعب غير الدورية (Directed Acyclic)، أي الشعب التي لا يمكن العودة عبرها إلى العقدة نفسها. العمليات PRIOR: تحصل على البيانات من العقدة الأب (node\'s parent). CONNECT_BY_ROOT: تحصل على البيانات من العقدة الجذرية. أشباه الأعمدة Pseudocolumns LEVEL: تشير إلى مسافة العقدة من جذرها. CONNECT_BY_ISLEAF: تشير إلى عقدة بدون فروعها. CONNECT_BY_ISCYCLE: تشير إلى عقدة ذات مرجع دائري (circular reference). الدوال SYS_CONNECT_BY_PATH: تعيد سلسلة نصية تمثّل المسار من الجذر إلى العقدة. ترجمة -وبتصرّف- للفصل 46 من الكتاب SQL Notes for Professionals'; preg_match_all($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