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

/
/
gim

Test String

Code Generator

Language

Generated Code

// include the latest version of the regex crate in your Cargo.toml extern crate regex; use regex::Regex; fn main() { let regex = Regex::new(r#"(?im)(?|^(?=(\".*?\"|[^\r\n\"]+)@)(?!.*?@(\..*?\.|\..*?|.*?\.|.{256,})$)(?=(.*?@([a-z0-9\-]{1,63}\.)+|^)[a-z0-9\-\.]{1,64}$)((?!\.|^.*?\.{2,}.*?@)[a-z0-9_\-\.\"!#$%&'*+ \/=?^`{|}~]{1,64}@(?<!\.@)(?!\-|.*?(\.\.|@).*?)([^\.]{1,63}|([a-z0-9\-\.]{1,63})+)(?<!\-)\.[a-z\d\-]{2,24})$)"#).unwrap(); let string = "Valid email addresses \"acc\"@bcc.ccc simple@example.com very.common@example.com disposable.style.email.with+symbol@example.com other.email-with-hyphen@example.com fully-qualified-domain@example.com user.name+tag+sorting@example.com x@example.com example-indeed@strange-example.com \" \"@example.org #!$%&'*+-/=?^_`{}|~@example.org example@s.example [ === WILL NEED TO CHECK THESE === ] \"()<>[]:,;@\\\\\\\"!#$%&'-/=?^_`{}| ~.a\"@example.org \"very.(),:;<>[]\\\".VERY.\\\"very@\\\\ \\\"very\\\".unusual\"@strange.example.com user@[2001:DB8::1] admin@mailserver1 Invalid email addresses: Abc.example.com A@b@c@example.com a\"b(c)d,e:f;g<h>i[j\\k]l@example.com just\"not\"right@example.com this is\"not\\allowed@example.com this\\ still\\\"not\\\\allowed@example.com 1234567890123456789012345678901234567890123456789012345678901234+x@example.com john..doe@example.com john.doe@example..com"; // result will be an iterator over tuples containing the start and end indices for each match in the string let result = regex.captures_iter(string); for mat in result { println!("{:?}", mat); } }

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 Rust, please visit: https://docs.rs/regex/latest/regex/