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

/
/
ig

Test String

Code Generator

Language

Generated Code

$re = '/([^\[a-z_0-9\-]|^)([a-z_\-][a-z0-9_\-]*:)/i'; $str = 'Return-Path: Received: from out.ipsmtp4nec.opaltelecom.net (out.ipsmtp4nec.opaltelecom.net [62.24.202.76]) by smartermail.divtech.co.za with SMTP; Mon, 6 Jul 2015 12:59:14 +0200 X-SMTPAUTH: sailor26@tiscali.co.uk X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: A2DSrwBOXppVPOPoVl0aAUErgmdUYIMfp3gMBgGBA4IZK4VrAYJ3V4ckhW8EKYEFTQEBAQEBAQcBAQEBQAE/HwEBIAECAoNdAQIMGzMuCgYDAQIPHw4COwoCCAEGCQESCAmICAMWCZFaoGKWHYYdhS6CTR6FCi+BFAWFXAqOLQIBhGGFJ4FfkTmHHYFvAQEIAQEBAQEBgiI+MYJLAQEB X-IPAS-Result: A2DSrwBOXppVPOPoVl0aAUErgmdUYIMfp3gMBgGBA4IZK4VrAYJ3V4ckhW8EKYEFTQEBAQEBAQcBAQEBQAE/HwEBIAECAoNdAQIMGzMuCgYDAQIPHw4COwoCCAEGCQESCAmICAMWCZFaoGKWHYYdhS6CTR6FCi+BFAWFXAqOLQIBhGGFJ4FfkTmHHYFvAQEIAQEBAQEBgiI+MYJLAQEB X-Header: TalkTalk X-IronPort-AV: E=Sophos;i=""5.15,414,1432594800""; d=""scan\'208,217"";a=""693647776"" Received: from 93-86-232-227.dynamic.isp.telekom.rs (HELO smtp.tiscali.co.uk) ([93.86.232.227]) by out.ipsmtp4nec.opaltelecom.net with ESMTP; 06 Jul 2015 11:59:04 +0100 Message-ID: From: "jonjon.bracq" To: "Webtickets" , "Webtickets Highlights" , "RYA" , "www jobonyachts com ADMIN" , "RYA InBrief" , "RYA InBrief" , "Webtickets Highlights" , "Webtickets Regional Highlights" , "RYA InBrief" Subject: =?ISO-8859-1?Q?FW=3AFrom=3Ajonjon.bracq=40yahoo.com?= Date: Thu, 26 Jun 2015 11:59:43 +0000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00BE_8320AA74.4FC1860E" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 16.4.3522.110 X-MIMEOLE: Produced By Microsoft MimeOLE V16.4.3522.110 X-SmarterMail-Spam: SPF_Pass, RHSBL, UCEProtect Level 1, Bayesian Filtering, ISpamAssassin 0 [raw: 0], DK_None, DKIM_None, Custom Rules [] X-SmarterMail-TotalSpamWeight: 12'; preg_match_all($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