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

r"
"
s

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"(?<=has been denied).*(401 to \d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})" test_str = ("2016-02-14 15:55:39.1094 Info HttpServer: HTTP Response 200 to 192.168.0.3. Time: 3ms. https://192.168.0.10:8920/emby/users/public\n" "2016-02-14 15:55:43.8597 Info HttpServer: HTTP POST https://192.168.0.10:8920/emby/Users/authenticatebyname. UserAgent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:44.0) Gecko/20100101 Firefox/44.0\n" "2016-02-14 15:55:43.8718 Info UserManager: Authentication request for <username> has been denied.\n" "2016-02-14 15:55:43.8820 Error DtoUtils: ServiceBase<TRequest>::Service Exception\n" " *** Error Report ***\n" " Version: 3.0.5821.0\n" " Command line: /usr/lib/emby-server/bin/MediaBrowser.Server.Mono.exe -programdata /var/lib/emby-server -restartpath /usr/lib/emby-server/restart.sh\n" " Operating system: Unix 3.19.0.25\n" " Processor count: 8\n" " 64-Bit OS: True\n" " 64-Bit Process: True\n" " Program data path: /var/lib/emby-server\n" " Mono: 4.2.1 (Stable 4.2.1.102/6dd2d0d Thu Dec 3 04:04:55 UTC 2015)\n" " Application Path: /usr/lib/emby-server/bin/MediaBrowser.Server.Mono.exe\n" " Invalid user or password entered.\n" " MediaBrowser.Controller.Net.SecurityException\n" " at MediaBrowser.Server.Implementations.Session.SessionManager+<AuthenticateNewSession>c__asyncC.MoveNext () <0x41c76b00 + 0x0080b> in <filename unknown>:0\n" " --- End of stack trace from previous location where exception was thrown ---\n" " at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <0x7fa7314f36d0 + 0x00029> in <filename unknown>:0\n" " at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) <0x7fa7314f16b0 + 0x000a7> in <filename unknown>:0\n" " at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) <0x7fa7314f1630 + 0x0006b> in <filename unknown>:0\n" " at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) <0x7fa7314f15e0 + 0x0003a> in <filename unknown>:0\n" " at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1+ConfiguredTaskAwaiter[TResult].GetResult () <0x7fa7314f1d10 + 0x00017> in <filename unknown>:0\n" " at MediaBrowser.Api.UserService+<Post>c__async1.MoveNext () <0x41c75ea0 + 0x00680> in <filename unknown>:0\n\n" "2016-02-14 15:55:43.8849 Error HttpServer: Error processing request for /emby/Users/authenticatebyname\n" " *** Error Report ***\n" " Version: 3.0.5821.0\n" " Command line: /usr/lib/emby-server/bin/MediaBrowser.Server.Mono.exe -programdata /var/lib/emby-server -restartpath /usr/lib/emby-server/restart.sh\n" " Operating system: Unix 3.19.0.25\n" " Processor count: 8\n" " 64-Bit OS: True\n" " 64-Bit Process: True\n" " Program data path: /var/lib/emby-server\n" " Mono: 4.2.1 (Stable 4.2.1.102/6dd2d0d Thu Dec 3 04:04:55 UTC 2015)\n" " Application Path: /usr/lib/emby-server/bin/MediaBrowser.Server.Mono.exe\n" " Invalid user or password entered.\n" " ServiceStack.HttpError\n" " No Stack Trace Available\n\n" "2016-02-14 15:55:43.8913 Info HttpServer: HTTP Response 401 to 192.168.0.3. Time: 32ms. https://192.168.0.10:8920/emby/Users/authenticatebyname\n") matches = re.search(regex, test_str, re.DOTALL) 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