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"
"
gm

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"\S+\d\.\d+" test_str = ("Internet Uplink FON 41.79.9.117 : Successful\n" "Microtik 194.201.253.246 : Successful\n" "Rooftop Switch 213.150.96.166: Successful\n\n" " TELNET TEST\n" " telnet mail.kenyaweb.com 25 : Connected to mail.kenyaweb.com. Escape character is '^]'. 220 mail.kenyaweb.com ESMTP Postfix\n" " telnet mail.kenyaweb.com 110: Connected to mail.kenyaweb.com. Escape character is '^]'. +OK POP3 ready\n\n" " MAIL SERVERS\n" " mail.kenyaweb.com 194.201.253.165 : Successful\n" " Relay.kenyaweb.com 194.201.253.124 : Successful\n" " pop.kenyaweb.com 194.201.253.11 : Successful\n" " hosting.kenyaweb.com 194.201.253.132 : Successful\n\n" " WEB SERVERS\n" "Web server 1 194.201.253.70 : Successful\n" "Web server 2 194.201.253.8 : Successful\n" "Web Server 3 194.201.253.5 : Successful\n" "sungura.kenyaweb.com 192.64.112.132: Successful\n" " \n\n" " DNS\n" " Linux.form-net.com 194.201.253.105 : Successful\n" " ns200.kenyaweb.com 194.201.253.186 : Successful\n" " ns201.kenyaweb.com 194.201.253.189 : Successful\n" " ns203.kenyaweb.com 63.250.47.221 : Successful\n\n" " BROWSE TEST\n" " www.kenyaweb.com http://www.kenyaweb.com : Successful\n" " www.yahoo.com http://www.yahoo.com : Successful\n" " www.google.com http://www.google.com : Successful\n\n" " MAIL TEST\n" " Mail.Kenyaweb to yahoo : Received\n" " Mail.Kenyaweb to gmail : Received\n" " Yahoo to Mail.Kenyaweb : Received\n" " Gmail to Mail.Kenyaweb : Received") matches = re.finditer(regex, test_str, re.MULTILINE) 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