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
  • Match everything enclosed
    (?:...)
  • Capture everything enclosed
    (...)
  • 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"
"

Test String

Code Generator

Generated Code

# coding=utf8 # the above tag defines encoding for this document and is for Python 2.x compatibility import re regex = r".*@(\S+)" test_str = ("From: <email@example.com> FROM name fails\n\n" "Closed (fixed)\n" "Project: \n" "SMTP Authentication Support\n" "Version: \n" "6.x-1.0-beta5\n" "Component: \n" "Code\n" "Priority: \n" "Normal\n" "Category: \n" "Bug report\n" "Assigned: \n" "José San Martin\n" "Reporter: \n" "goose2000\n" "Created: \n" "July 8, 2008 - 12:54\n" "Updated: \n" "October 5, 2012 - 19:01\n" "Log in or register to update this issue\n" "Jump to:\n" "Most recent attachment\n" "Hi, my development site is running on IIS with SMTP server. Mail is working fine when creating new users or getting a password reset. I have built a webform and upon submitting I'll get this error:\n\n\n" " * warning: mail() [function.mail]: SMTP server response: 501 5.5.4 Invalid Address in C:\\Inetpub\\wwwroot\\BHI_dev\\includes\\mail.inc on line 193.\n" " * Unable to send e-mail. Please contact the site admin, if the problem persists.\n\n" "The address I use in my testing are in fact completely valid. Seems like webform is not playing nice with the core somehow. Further ideas?\n\n" "Using Drupal 6.2.\n\n" "Thanks.\n\n" "Files: \n" "Comment File Size Author\n" "#25 smtp_279836.patch 694 bytes scttnlsn\n" "#13 smtp_module_name_patch_279836_01.patch 724 bytes franz\n" "#6 smtp_module_name_patch_279836_01.patch 724 bytes rfay\n" "Comments\n" " goose2000’s picture\n" "Comment #1goose2000 CreditAttribution: goose2000 commented 8 years ago\n" "Priority: Critical » Minor\n" "This seems to be an IIS SMTP issue only. See here:\n\n" "http://drupal.org/node/33967\n\n" "Easy work around is to have no 'name' text , just the email address when you configure webform.\n" "Think it may still be fixable at the code? I set it to 'minor' now.\n\n" "Working great, one of the best modules around.\n" "Log in or register to post comments\n" " quicksketch’s picture\n" "Comment #2quicksketch CreditAttribution: quicksketch commented 7 years ago\n" "Title: Email Invalid Address » \"Name\" <email@example.com> FROM name fails\n" "Project: Webform » SMTP Authentication Support\n" "Version: 6.x-2.1.1 » 6.x-1.0-beta3\n" "Moving to the SMTP module.\n\n" "To summarize, Webform users have not been able to send e-mails when using the SMTP module and the FROM e-mail addresses are formatted as \"First Last\" <email@example.com>. The name is properly mime_header_encoded when necessary.\n\n" "Any users experiencing this issue, please update with the version of SMTP module you're using.") matches = re.search(regex, test_str) 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