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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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

"
"

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#"\"app\":\s\{((.|\n)*)\"local\""#).unwrap(); let string = "{ \"app\": { \"local\": \"True\", \"dependency_env\": \"dev\" }, \"engine\": { \"disable_jwt_check\": \"true\", \"jwt_private_key\": \"sph59tZqVrjqz3BiVUnXvKRgd6BxDkN2E+TAjy96wfASO4/5DGJIQlZvnNSt4H7wKLQ0b1J5AdNJ7315B9My6w==\", \"jwt_issuer\": \"https://hbgpmwapi-dev.kantar.com\" }, \"azure\": { \"app_id\": \"efe4d19e-880e-480e-8e0c-f86c9fd5872c\", \"app_key\": \"b1e5em8uILeqAI.0jt=zg[mJHSaaHKz:\", \"env\": \"dev\", \"storage_key\": \"pKhqboH2XDRpYNLco4vyPapHNd7Ao/BO28yFBD0ooSSn/828NLMfKkkzdrqUyeeA2312Y9xAix1T/YdAHkbZCw==\", \"storage_container\": \"marketingpressure\", \"storage_endpoint\": \"https://hbgenginestorage.blob.core.windows.net\" }, \"URL\": { \"main\": \"http://localhost:3838\" } }"; // result will be a tuple containing the start and end indices for the first match in the string let result = regex.captures(string); let (start, end) = match result { Some((s, e)) => (s, e), None => { // ... } }; println!("{}", &string[start, end]); }

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/