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
Processing...

Test String

Code Generator

Language

Generated Code

import re regex = re.compile(r"^[a-z0-9]+[\._]?[a-z0-9]+[@]\w+[.]\w{2,3}$", flags=re.MULTILINE) test_str = ("###################### Valid Emails ########################################################\n" "######################## German, Austrian, international ###################################\n\n" "janedoe@web.de\n" "jane.doe@web.de\n" "jdoe@web.de\n" "jane-doe@web.de\n" "jane@web.de\n" "doe@web.de\n" "janed@web.de\n" "doej@web.de\n" "jane_doe@web.de\n" "j.doe@web.de\n" "jane.d@web.de\n\n" "janedoe@t-online.de\n" "jane.doe@t-online.de\n" "jdoe@t-online.de\n" "jane-doe@t-online.de\n" "jane@t-online.de\n" "janed@t-online.de\n" "doej@t-online.de\n" "jane_doe@t-online.de\n" "j.doe@t-online.de\n" "jane.d@t-online.de\n\n" "janedoe@hotmail.de\n" "jane.doe@hotmail.de\n" "jdoe@hotmail.de\n" "jane-doe@hotmail.de\n\n" "janedoe@gmx.de\n" "jane.doe@gmx.de\n" "jdoe@gmx.de\n" "jane-doe@gmx.de\n\n\n" "jane.doe@post.at\n" "jane-doe@post.at\n" "janedoe@post.at\n" "jane@post.at\n" "john.doe@austrian.com\n" "horneaudrey@fulbright.at\n\n\n" "#####################################################################################\n" "########################## Not valid email ##########################################\n" ".test@gmail.com\n" "-test@gmail.com\n" "t.-.est@gmail.com\n" ".test.@gmail.com\n" "test.@gmail.com\n" "test.@.gmail.com\n" "test@.gmail.com\n" "test@.gmail.com.\n" "test@gmail.com.\n\n" "\"email\"@example.com\n\n" "#@%^%#$@#$@#.com\n" "@example.com\n" "Joe Smith <email@example.com>\n" "email.example.com\n" "email@example@example.com\n" ".email@example.com\n" "email.@example.com\n" "email..email@example.com\n" "あいうえお@example.com\n" "email@example.com (Joe Smith)\n" "email@example\n" "email@-example.com\n" "email@example.web\n" "email@111.222.333.44444\n" "email@example..com\n" "Abc..123@example.com") matches = regex.finditer(test_str) for match_num, match in enumerate(matches, start=1): print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}") for group_num, group in enumerate(match.groups(), start=1): print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")

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