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

/
/
gimx

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#"(?imx)(?(DEFINE) (?<quote>['"]) (?<pair> (?> \w+ |(?: (?<pairQuote>(?&quote))[^'"]+?\k<pairQuote> ) ) \s*\: ) (?<string> (?<stringQuote>(?&quote))[\S\s]*?(?<!\\)\k<stringQuote> ) (?<integer>\-?\d+(?:\.\d+)?(?:e[-+]\d+)?) (?<scalar>true|false|null|(?&integer)) (?<elements> \s*(?&value) (?(R&array)|(?>(?:\s*\,(?&elements))|\s*)) ) (?<array>\[(?>(?&elements)|\s*)\]) (?<value> (?&object) |(?&string) |(?&scalar) |(?&array) ) (?<members> \s*(?&pair)\s*(?&value) (?(R&object)|(?>(?:\s*\,(?&members))|\s*)) ) (?<object>\{(?&members)?\}) ) \A(?&object)\Z"#).unwrap(); let string = "{\"menu\": { \"header\": \"SVG Viewer\", \"items\": [ {\"id\": \"Open\"}, {\"id\": \"OpenNew\", \"label\": \"Open New\"}, null, {\"id\": \"ZoomIn\", \"label\": \"Zoom In\"}, {\"id\": \"ZoomOut\", \"label\": \"Zoom Out\"}, {\"id\": \"OriginalView\", \"label\": \"Original View\"}, null, {\"id\": \"Quality\"}, {\"id\": \"Pause\"}, {\"id\": \"Mute\"}, null, {\"id\": \"Find\", \"label\": \"Find...\"}, {\"id\": \"FindAgain\", \"label\": \"Find Again\"}, {\"id\": \"Copy\"}, {\"id\": \"CopyAgain\", \"label\": \"Copy Again\"}, {\"id\": \"CopySVG\", \"label\": \"Copy SVG\"}, {\"id\": \"ViewSVG\", \"label\": \"View SVG\"}, {\"id\": \"ViewSource\", \"label\": \"View Source\"}, {\"id\": \"SaveAs\", \"label\": \"Save As\"}, null, {\"id\": \"Help\"}, {\"id\": \"About\", \"label\": \"About Adobe CVG Viewer...\"} ], \"test\": [ \"Some value\", 4, null,{} ], \"empty_array\":[-0.34E+4] }}"; // 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/