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

r"
"
gim

Test String

Substitution

Processing...

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@\"]{1,64}(\.[^<>()\[\]\.,;:\s@\"]+)*)|(\".+\"))@\[*(?!.*?\.\.)(([^<>()[\]\.,;\s@\"]+\.?)+[^<>()[\]\.,;\s@\"]{2,})\]?" 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\"," # You can manually specify the number of replacements by changing the 4th argument result = re.sub(regex, subst, test_str, 0, re.IGNORECASE | re.MULTILINE) if result: print (result) # 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