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

/
/
gu

Test String

Code Generator

Language

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r"Authentication-results:.+?sender IP.+\R?.+?mailfrom=(.+?);" test_str = ("Return-path: <JaneSmith@SomeDummyCo.com>\n" "Received: from ms11p00im-qufv17093501.mac.com ([17.58.36.64])\n" " by ms24534.mac.com\n" " (Oracle Communications Messaging Server 8.0.1.3.20170906 64bit (built Sep 6\n" " 2017)) with ESMTP id <0PE4008Z5RC0PLA0@ms24534.mac.com> for\n" " JohnDoe@icloud.com; Mon, 27 Aug 2018 17:31:12 +0000 (GMT)\n" "Original-recipient: rfc822;JohnDoe@icloud.com\n" "Received: from NAM04-SN1-obe.outbound.protection.outlook.com\n" " (mail-eopbgr700137.outbound.protection.outlook.com [40.107.70.137])\n" " by ms11p00im-qufv17093501.me.com\n" " (Oracle Communications Messaging Server 8.0.2.2.20180531 64bit (built May 31\n" " 2018)) with ESMTPS id <0PE400K2IRBZ4F00@ms11p00im-qufv17093501.me.com> for\n" " JohnDoe@icloud.com (ORCPT JohnDoe@icloud.com); Mon,\n" " 27 Aug 2018 17:31:12 +0000 (GMT)\n" "X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0\n" " clxscore=1005 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0\n" " bulkscore=0 classifier=clx:Deliver adjust=0 reason=mlx scancount=1\n" " engine=8.0.1-1807170000 definitions=main-1808270184\n" "X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,,\n" " definitions=2018-08-27_07:,, signatures=0\n" "Authentication-results: ms11p00im-qufv10093201.me.com; dmarc=none\n" " header.from=apoemail.us\n" "Authentication-results: ms11p00im-qufv10113901.me.com; spf=pass\n" " (ms11p00im-qufv10113901.me.com: domain of JaneSmith@SomeDummyCo.com designates\n" " 40.107.70.137 as permitted sender) smtp.mailfrom=JaneSmith@SomeDummyCo.com\n" "Received-SPF: pass (ms11p00im-qufv10113901.me.com: domain of\n" " JaneSmith@SomeDummyCo.com designates 40.107.70.137 as permitted sender)\n" " receiver=ms11p00im-qufv10113901.me.com; client-ip=40.107.70.137;\n" " helo=NAM04-SN1-obe.outbound.protection.outlook.com;\n" " envelope-from=JaneSmith@SomeDummyCo.com\n" "Authentication-results: ms11p00im-qufv17063001.me.com; dkim=pass (1024-bit key)\n" " header.d=NETORGFT744019.onmicrosoft.com\n" " header.i=@NETORGFT744019.onmicrosoft.com header.b=fYoFciKN\n" "DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;\n" " d=NETORGFT744019.onmicrosoft.com; s=selector1-apoemail-us;\n" " h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;\n" " bh=ZUfrOM+P5LAWsuKD/Lnb58GuE4orISbImwlBF3a/vyc=;\n" " b=fYoFciKNtylrXwhibBhDmgiw70cFEaUP4XADRpc2cfX3M/4o94Uc7kMGMdo7wj1KqH/d/ShRSn1YX36qzEnW5yA26XIloXj/bt7iZX2LN5boJlI6OaE6DFUIKivm2Cfvl4Q9wckPQRot76ogx/NeYCwfJvD/OgGybwJWjoLQQJo=\n" "Received: from DM3PR19MB0521.namprd19.prod.outlook.com (10.164.248.145)\n" " by DM3PR19MB0825.namprd19.prod.outlook.com (10.166.164.151)\n" " with Microsoft SMTP Server\n" " (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384)\n" " id 15.20.1080.14; Mon, 27 Aug 2018 17:31:09 +0000\n" "Received: from DM3PR19MB0521.namprd19.prod.outlook.com\n" " ([fe80::69c8:8da3:dc38:8caa]) by DM3PR19MB0521.namprd19.prod.outlook.com\n" " ([fe80::69c8:8da3:dc38:8caa%5]) with mapi id 15.20.1080.015; Mon,\n" " 27 Aug 2018 17:31:09 +0000\n" "From: John Doe <JaneSmith@SomeDummyCo.com>\n" "To: John Doe <JohnDoe@icloud.com>\n" "Subject: AutoResponder - Acme Inc - New Client Questionnaire - - Steven\n" " Plain Text TEST 03/12/1971\n" "Thread-topic: AutoResponder - Acme Inc - New Client Questionnaire - -\n" " Steven Plain Text TEST 03/12/1971\n" "Thread-index: AQHUPiu+8RdF6Tdpg0SO88Zlg/iLzQ==\n" "Date: Mon, 27 Aug 2018 17:31:09 +0000\n" "Message-id: <D7A99F58.1E1AA%JaneSmith@SomeDummyCo.com>\n" "Accept-Language: en-US\n" "Content-language: en-US\n" "X-MS-Has-Attach:\n" "Authentication-results: spf=none (sender IP is )\n" " smtp.mailfrom=JaneSmith@SomeDummyCo.com;\n" "X-Originating-IP: [98.195.128.79]\n" "X-Microsoft-Exchange-Diagnostics:\n") matches = re.finditer(regex, test_str, re.UNICODE) for matchNum, match in enumerate(matches, start=1): print ("Match {matchNum} was found at {start}-{end}: {match}".format(matchNum = matchNum, start = match.start(), end = match.end(), match = match.group())) for groupNum in range(0, len(match.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = match.start(groupNum), end = match.end(groupNum), group = match.group(groupNum))) # Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.

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 Python, please visit: https://docs.python.org/3/library/re.html