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

/
/
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"\b[a-zA-Z1-9]((([]!#$%^&*()])(?!\g<-1>))|[a-zA-Z1-9]){0,63}((?<![]!#$%^&*()])@)(\w+\.)+(com|net|gov|mil|org|edu)\b" test_str = ("(850)867-5309\n" "850-867-5309 \n" "(850_867_5309)\n" "850.867.5309\n" "[Hello]\n" "C:\\windows\\system32\n" "!MrColdsnow@jimbob.steve.com\n" "BaconTaters@osu.edu\n" "1.2.3.4\n" "11.22.33.44\n" "111.222.111.222\n" "192.168.0.5\n" "1234.1234.1234.1234\n" "956.458.875.259\n" "...\n" "123-45-6789\n" "ABB\n" "ABAB\n" "The quick brown dog jumped over the lazy programmer.\n" "There are fifty states in the United States.\n" "Breathe because RegEx is easy.\n" "42 ( Answer to the Ultimate Question of Life, the Universe, and Everything )\n" "73 (the best number) ( 7 is the 4th prime number and 3 is the 2nd prime number (42) )\n" " (not to mention, 73 is the 21st prime number and 37 is the 12th (both numbers mirrored) and\n" " 73 in binary is 1001001 (a palindrome) )\n" "bat cat hat rat brat chat\n" "eat fat gat lat mat oat pat sat vat \n" "my dog likes a good hotdog\n" "dogs like hotdogs but not our \"person\" dogma\n" "dog\n" "2dog\n" "snoop2dog\n" "10\n" "150\n" "345\n" "14\n" "0789\n" "7980\n" "ICMP echo request\n" "ICMP echo reply\n" "deed peep noon Otto Abba\n" "level kayak madam radar refer civic\n" "redder revver\n" "racecar rotator deified repaper reviver\n" "List of trucks that are better than the F150:\n" "1. GMC Sierra\n" "2. Chevy Silverado\n" "3. Toyota Tundra\n" "4. Nissan Titan\n" "5. Toyota Tacoma\n" "6. GMC Canyon\n" "7. Nissan Frontier\n" "8. Jeep Gladiator\n" "9. Honda Ridgeline\n" "10. Chevy Cavalier\n" "moose mouse mooooose m3se\n" "Mississippi") 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