Regular Expressions 101

Save & Share

  • Current Version: 1
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java
  • .NET 7.0 (C#)
  • Rust
  • PCRE (Legacy)
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests
Sponsors
There are currently no sponsors. Become a sponsor today!
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

// 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#"(?xi)(?={)(?(DEFINE) (?<number> [0-9]+(?:\.[0-9]*)?(?:e[+-]?[0-9]+)?) (?<string> \\" (?>[^"\\]+|\\\\(?:[^\\]|\\.))* \\" ) (?<boolean> true | false | null) (?<pair> (?: \g<string> | \g<number>) \s* : \s* (?: \g<string> | \g<number> | \g<boolean> | \g<json> | \g<array> ) ) (?<array> \[\s* \g<json> (?: \s*,\s* \g<json>)* \s*]) (?<json> { \s* \g<pair> (?:\s*,\s* \g<pair>)* }) ) \g<json>"#).unwrap(); let string = "\"b<---------------->{\\\"status\\\":\\\"ok\\\",\\\"plugin_version\\\":\\\"1.2.6\\\",\\\"post\\\":{\\\"id\\\":7598,\\\"type\\\":\\\"post\\\",\\\"slug\\\":\\\"honeycrisp-apple-sangria-recipe\\\",\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-recipe\\\\/\\\",\\\"status\\\":\\\"publish\\\",\\\"title\\\":\\\"Honeycrisp Apple Sangria Recipe\\\",\\\"title_plain\\\":\\\"Honeycrisp Apple Sangria Recipe\\\",\\\"content\\\":\\\"<div class=\\\\\\\"pin-it-btn-wrapper\\\\\\\"><a href=\\\\\\\"\\\\/\\\\/www.pinterest.com\\\\/pin\\\\/create\\\\/button\\\\/?url=http%3A%2F%2Fwww.bigbigbutts.com%2F2013%2F08%2Fhoneycrisp-apple-sangria-recipe%2F&media=http%3A%2F%2Fwww.bigbigbutts.com%2Fwp-content%2Fuploads%2F2013%2F08%2Fhoneycrisp-apple-sangria.jpg&description=Honeycrisp%20Apple%20Sangria%20Recipe\\\\\\\" data-pin-do=\\\\\\\"buttonBookmark\\\\\\\" data-pin-config=\\\\\\\"none\\\\\\\" rel=\\\\\\\"nobox\\\\\\\"><\\\\/a><\\\\/div>\\\",\\\"raw_content\\\":\\\"\\\",\\\"excerpt\\\":\\\"\\\",\\\"date\\\":\\\"2013-08-24T11:18:07+00:00\\\",\\\"modified\\\":\\\"2014-04-24T09:45:00+00:00\\\",\\\"author\\\":{\\\"id\\\":2,\\\"slug\\\":\\\"gia\\\",\\\"name\\\":\\\"gia\\\",\\\"first_name\\\":\\\"gia\\\",\\\"last_name\\\":\\\"Wenner chia\\\",\\\"nickname\\\":\\\"gia\\\",\\\"url\\\":\\\"http:\\\\/\\\\/giawennerchia.com\\\",\\\"description\\\":\\\"gia Wenner chia is a writer and mom who gets paid to obsess over Pinterest and blogs for Ahalogy, a Cincinnati-based startup. She lives in her hometown of West Chester, Ohio, with her husband, two young children, and their dog.\\\"},\\\"attachments\\\":[{\\\"id\\\":7599,\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"slug\\\":\\\"honeycrisp-apple-sangria\\\",\\\"title\\\":\\\"honeycrisp-apple-sangria\\\",\\\"description\\\":\\\"\\\",\\\"caption\\\":\\\"\\\",\\\"parent\\\":7598,\\\"mime_type\\\":\\\"image\\\\/jpeg\\\",\\\"images\\\":{\\\"full\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"width\\\":580,\\\"height\\\":406},\\\"thumbnail\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-150x150.jpg\\\",\\\"width\\\":150,\\\"height\\\":150},\\\"medium\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-300x210.jpg\\\",\\\"width\\\":300,\\\"height\\\":210},\\\"large\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"width\\\":580,\\\"height\\\":406},\\\"Mini Square\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-70x70.jpg\\\",\\\"width\\\":70,\\\"height\\\":70},\\\"Square\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-115x115.jpg\\\",\\\"width\\\":115,\\\"height\\\":115},\\\"Featured Tabs\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-150x225.jpg\\\",\\\"width\\\":150,\\\"height\\\":225}}}],\\\"featured_image\\\":{\\\"id\\\":7599,\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"slug\\\":\\\"honeycrisp-apple-sangria\\\",\\\"title\\\":\\\"honeycrisp-apple-sangria\\\",\\\"description\\\":\\\"\\\",\\\"caption\\\":\\\"\\\",\\\"parent\\\":7598,\\\"mime_type\\\":\\\"image\\\\/jpeg\\\",\\\"images\\\":{\\\"full\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"width\\\":580,\\\"height\\\":406},\\\"thumbnail\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-150x150.jpg\\\",\\\"width\\\":150,\\\"height\\\":150},\\\"medium\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-300x210.jpg\\\",\\\"width\\\":300,\\\"height\\\":210},\\\"large\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria.jpg\\\",\\\"width\\\":580,\\\"height\\\":406},\\\"Mini Square\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-70x70.jpg\\\",\\\"width\\\":70,\\\"height\\\":70},\\\"Square\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-115x115.jpg\\\",\\\"width\\\":115,\\\"height\\\":115},\\\"Featured Tabs\\\":{\\\"url\\\":\\\"http:\\\\/\\\\/www.bigbigbutts.com\\\\/wp-content\\\\/uploads\\\\/2013\\\\/08\\\\/honeycrisp-apple-sangria-150x225.jpg\\\",\\\"width\\\":150,\\\"height\\\":225}}}}}<random shit><dafkdjkfjdaksf\""; // 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/