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

Substitution
Processing...

Code Generator

Language

Generated Code

import re regex = re.compile(r"^(([^<>()\[\]\.,;:\s@\"]{1,64}(\.[^<>()\[\]\.,;:\s@\"]+)*)|(\".+\"))@\[*(?!.*?\.\.)(([^<>()[\]\.,;\s@\"]+\.?)+[^<>()[\]\.,;\s@\"]{2,})\]?", flags=re.IGNORECASE | re.MULTILINE) test_str = ("prettyandsimple@example.com\n" "very.common@example.com\n" "disposable.style.email.with+symbol@example.com\n" "other.email-with-dash@example.com\n\n" "(one-letter local part)\n" "x@example.com\n\n" "\"much.more unusual\"@example.com\n" "\"very.unusual.@.unusual.com\"@example.com\n" "\"very.(),:;<>[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com\n" "example-indeed@strange-example.com\n" " \n" "(local domain name with no TLD)\n" "admin@mailserver1\n\n" "#!$%&'*+-/=?^_`{}|~@example.org\n" "\"()<>[]:,;@\\\\\\\"!#$%&'*+-/=?^_`{}| ~.a\"@example.org\n\n" "(space between the quotes)\n" "\" \"@example.org\n\n" "example@localhost\n" "example@s.solutions\n" "user@com\n" "user@localserver\n" "user@[2001:DB8::1][\n" "user@[IPv6:2001:db8::1]\n" "©other.email-with-dash@example.com\n" "?prettyandsimple@example.com\n" "用户@例子.广告\n" "अजअय@डाअटा.भारत\n" "квіточка@пошта.укр\n" "θσερ@εχαμπλε.ψομ\n" "Dörte@Sörensen.example.com\n" "аджай@экзампл.рус\n\n\n" "Invalid email addresses[edit]\n\n" "(no @ character)\n" "Abc.example.com\n\n" "(only one @ is allowed outside quotation marks)\n" "A@b@c@example.com\n\n" "(none of the special characters in this local part are allowed outside quotation marks)\n" "a\"b(c)d,e:f;g<h>i[j\\k]l@example.com\n\n" "(quoted strings must be dot separated or the only element making up the local part)\n" "just\"not\"right@example.com\n\n" "(spaces, quotes, and backslashes may only exist when within quoted strings and preceded by a backslash)\n" "this is\"not\\allowed@example.com\n\n" "(even if escaped (preceded by a backslash), spaces, quotes, and backslashes must still be contained by quotes)\n" "this\\ still\\\"not\\\\allowed@example.com\n\n" "(double dot before @)\n" "john..doe@example.com\n" "with caveat: Gmail lets this through, Email address#Local-part the dots altogether\n\n" "(double dot after @)\n" "john.doe@example..com\n\n" "(exceeds 64 characters in local part)\n" "1234567890123456789012345678901234567890123456789012345678901234+x@example.com\n" "alskjnakjanv1wadfqaebbsfdfagfbnbKJANDVlvn13dcljnvzlkjbnadlkgf3cjnj@winnipeg.com\n") subst = "QuestionText = \"$1\"," result = regex.sub(subst, test_str) if result: print(result)

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