Regular Expressions 101

Save & Share

  • Regex Version: ver. 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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

r"
"
xsm

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""" ^Date:\ (?P<date>.+?$) .+? ^From:\ (?P<sender>.+?$) .+? ^To:\ (?P<to>.+?$) .+? ^cc:\ (?P<cc>.+?$) .+? ^Subject:\ (?P<subject>.+?$) """ test_str = ("Message-ID: <3490571.1075846143093.JavaMail.evans@thyme>\n" "Date: Wed, 8 Sep 1999 08:50:00 -0700 (PDT)\n" "From: steven.kean@enron.com\n" "To: kelly.kimberly@enron.com\n" "Subject: Re: India And The WTO Services Negotiation\n" "Mime-Version: 1.0\n" "Content-Type: text/plain; charset=us-ascii\n" "Content-Transfer-Encoding: 7bit\n" "X-From: Steven J Kean\n" "X-To: Kelly Kimberly\n" "X-cc: \n" "X-bcc: \n" "X-Folder: \\Steven_Kean_Dec2000_1\\Notes Folders\\All documents\n" "X-Origin: KEAN-S\n" "X-FileName: skean.nsf\n\n" "fyi\n" "---------------------- Forwarded by Steven J Kean/HOU/EES on 09/08/99 03:49 \n" "PM ---------------------------\n\n\n" "Joe Hillings@ENRON\n" "09/08/99 02:52 PM\n" "To: Joe Hillings/Corp/Enron@Enron\n" "cc: Sanjay Bhatnagar/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Terence H \n" "Thorn/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Ashok \n" "Mehta/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, John \n" "Ambler/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Steven J Kean/HOU/EES@EES, \n" "Jeffrey Sherrick/Corp/Enron@Enron \n" "Subject: Re: India And The WTO Services Negotiation \n\n" "Sanjay: Some information of possible interest to you. I attended a meeting \n" "this afternoon of the Coalition of Service Industries, one of the lead groups \n" "promoting a wide range of services including energy services in the upcoming \n" "WTO GATTS 2000 negotiations. CSI President Bob Vastine was in Delhi last week \n" "and met with CII to discuss the upcoming WTO. CII apparently has a committee \n" "looking into the WTO. Bob says that he told them that energy services was \n" "among the CSI recommendations and he recalls that CII said that they too have \n" "an interest.\n\n" "Since returning from the meeting I spoke with Kiran Pastricha and told her \n" "the above. She actually arranged the meeting in Delhi. She asked that I send \n" "her the packet of materials we distributed last week in Brussels and London. \n" "One of her associates is leaving for India tomorrow and will take one of \n" "these items to Delhi. \n\n" "Joe\n\n\n\n" "Joe Hillings\n" "09/08/99 11:57 AM\n" "To: Sanjay Bhatnagar/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT\n" "cc: Terence H Thorn/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Ashok \n" "Mehta/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, John \n" "Ambler/ENRON_DEVELOPMENT@ENRON_DEVELOPMENT, Steven J Kean/HOU/EES@EES, \n" "Jeffrey Sherrick/Corp/Enron@Enron (bcc: Joe Hillings/Corp/Enron)\n" "Subject: India And The WTO Services Negotiation\n\n" "Sanjay: First some information and then a request for your advice and \n" "involvment.") matches = re.search(regex, test_str, re.VERBOSE | re.DOTALL | re.MULTILINE) if matches: print ("Match was found at {start}-{end}: {match}".format(start = matches.start(), end = matches.end(), match = matches.group())) for groupNum in range(0, len(matches.groups())): groupNum = groupNum + 1 print ("Group {groupNum} found at {start}-{end}: {group}".format(groupNum = groupNum, start = matches.start(groupNum), end = matches.end(groupNum), group = matches.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