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

/
/
g

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#"("|\s)(?<key>(CN|C|O|OU|S))=(?<value>[^=\"]+)(?=(\s|"))"#).unwrap(); let string = "ssl_issuer=\"CN=DigiCert SHA2 High Assurance Server CA C=US O=DigiCert Inc OU=www.digicert.com\" ssl_hash=\"f41565b049f039e765a0f8be8271a4b4817b7378\" ssl_subject=\"CN=syndication.twitter.com C=US S=California O=Twitter, Inc. OU=Twitter Security\" ssl_start_time=\"Wed Jun 29 00:00:00 2016 UTC\" ssl_end_time=\"Mon Sep 16 12:00:00 2019 UTC\" ssl_type=\"X.509 Certificate\" ssl_extended_key_usage=\"Server Authentication, Client Authentication\" ssl_key_length=\"2048 bits\" ssl_key_usage=\"Digital Signature, Key Encipherment\" ssl_subject=\"CN=*.eu-west-1.webrootcloudav.com\" ssl_start_time=\"Tue Aug 22 00:00:00 2017 UTC\" ssl_end_time=\"Sat Sep 22 12:00:00 2018 UTC\" ssl_type=\"X.509 Certificate\" ssl_extended_key_usage=\"\" ssl_key_length=\"2048 bits\" ssl_key_usage=\"Digital Signature, Non-Repudiation, Key Encipherment\" ssl_subject=\"CN=*.us.static.hrsmart.com C=US S=Virginia O=Deltek, Inc. OU=Security Services\" ssl_start_time=\"Thu Jan 11 00:00:00 2018 UTC\" ssl_end_time=\"Sun Mar 31 12:00:00 2019 UTC\" ssl_type=\"X.509 Certificate\" ssl_extended_key_usage=\"Server Authentication, Client Authentication\" ssl_key_length=\"2048 bits\" ssl_key_usage=\"Digital Signature, Key Encipherment\" ssl_subject=\"CN=*.googleapis.com C=US S=California O=Google Inc\" ssl_start_time=\"Tue Mar 13 18:57:10 2018 UTC\" ssl_end_time=\"Tue Jun 5 18:17:00 2018 UTC\" ssl_type=\"X.509 Certificate\" ssl_extended_key_usage=\"Server Authentication, Client Authentication\" ssl_key_length=\"0 bits\" ssl_key_usage=\"Digital Signature, Certificate Signing, CRL Signing\" ssl_subject=\"CN=subscription.rhsm.redhat.com C=US S=North Carolina O=Red Hat, Inc. OU=Red Hat Network\" ssl_start_time=\"Thu May 18 16:30:24 2017 UTC\" ssl_end_time=\"Sat May 18 16:30:24 2019 UTC\" ssl_type=\"X.509 Certificate\" ssl_extended_key_usage=\"Server Authentication\" ssl_key_length=\"4096 bits\" ssl_key_usage=\"\""; // 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/