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
Processing...

Test String

Code Generator

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"(?i)(?!\bTAG_|\bSECUENCIA_)\w*").unwrap(); let string = " <DATOS> <SECUENCIA_A> <TAG_28E_A> <NUM_PAGINA_28E_A>String</NUM_PAGINA_28E_A> <IND_PAGINA_28E_A>String</IND_PAGINA_28E_A> </TAG_28E_A> <TAG_20C_SEME> <REFER_20C>String</REFER_20C> </TAG_20C_SEME> <TAG_23G_A> <FUNCION_23G>String</FUNCION_23G> <SUBFUNCION_23G>String</SUBFUNCION_23G> </TAG_23G_A> <TAG_98C_PREP> <FECHA_98C>String</FECHA_98C> <HORA_98C>String</HORA_98C> </TAG_98C_PREP> <TAG_98A_STAT> <FECHA_98A>String</FECHA_98A> </TAG_98A_STAT> <TAG_22F_SFRE> <IND_22F>String</IND_22F> </TAG_22F_SFRE> <TAG_22F_CODE> <IND_22F>String</IND_22F> </TAG_22F_CODE> <TAG_22F_STTY> <IND_22F>String</IND_22F> </TAG_22F_STTY> <TAG_22F_STBA> <IND_22F>String</IND_22F> </TAG_22F_STBA> <SECUENCIA_A1> <TAG_13A_LINK> <IND_13A>String</IND_13A> </TAG_13A_LINK> <TAG_20C_RELA> <REFER_20C>String</REFER_20C> </TAG_20C_RELA> </SECUENCIA_A1>"; // 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/