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

/
/
gm

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#"(?m)(?:\"(?:(?<=\"(?=[^\n]))[^\n]+?(?=(?<!\\))(?=\"))?\")|(\B'(?:(?<='(?=[^\n]))[^\n]+?(?=(?<!\\))(?='))?')"#).unwrap(); let string = " 1. Valid double-quoted strings: - \"Hello\" - \"This is a test\" - \"123\" - \"Special characters: @#$%^&*()_+\" - \"Escape sequence: \\n\" 2. Valid double-quoted strings with additional characters or variables: - \" test aaaaa \\\" \" + asdf - \" test \" + ( \"aaaaa\" ) + gdf - \" test \\\" \" + `\" aaaa \" + dfg - \" test ' aaaaa \\\" \" + dfg - \"\" 3. Valid double-quoted strings with special characters: - \"sas''as\\\"a1\\'2 ! -_?:sa\" - \"''\" - \"\\abnb\\ajhgf\\crt098& \\\"'\" 4. Invalid double-quoted strings: - \" test \" + ( \"aaaaa\" ) \\\" saf - \"\\\\ + \\* test \" \\$ \\. dsdfs - (\\\" test \\\" \" + \" aaaa \" sfgd - ' test ' + aas ( \"aaaaa\" ) + '\\ sd - '\\\\ + \\* test ' \\$ \\. trace - (' test ' as ' + ' aaaa ' - '\"\"' - '\"sas' - 'ads' - 'asdasd\\\"asdsa' - \"klkl\"klkl - \"asa\\'sasa\\\\\" - \\'\\\\\\' - \"hhhh\"klkl\" - 'jkjkjk'klklk' - '\\\"\\\\\\\"' - '' - '\\\"asa\\'sasa\\\\\\\"' - \"sasasasa\\\\\\\\\\\\\" 1. Valid single-quoted strings: - 'Hello' - 'This is a test' - '123' - 'Special characters: @#$%^&*()_+' - 'Escape sequence: \\n' 2. Valid single-quoted strings with additional characters or variables: - ' test aaaaa \\' ' + asdf - ' test ' + ( 'aaaaa' ) + gdf - ' test \\' ' + ' aaaa' + dfg - ' test \" aaaaa \\' ' + dfg - '' 3. Valid single-quoted strings with special characters: - 'sas\"\"as\\'a1\\\"2 ! -_?:sa' - '\"\"' - '\\abnb\\ajhgf\\crt098& \\'\"\"' 4. Invalid single-quoted strings: - ' test ' + ( 'aaaaa' ) \\' saf - '\\\\ + \\* test ' \\$ \\. dsdfs - (\\' test \\' + ' aaaa ' sfgd - \" test \\\" \" + \" aaaa \" sfgd - ' test ' + aas ( 'aaaaa' ) + '\\ sd - '\\\\ + \\* test ' \\$ \\. trace - (' test ' as ' + ' aaaa ' - \"''\" - 'sas\" - \"ads' - 'asdasd\\'asdsa' - \"klkl\"klkl - \"asa\\'sasa\\\\\" - \\'\\\\\\' - 'hhhh\"klkl\\'\\ - \\'jkjkjk\"klklk' - \"\\'\\\\\\'\" - '' - '\\\"asa\\'sasa\\\\\\\"' - 'sasasasa\\\\\\\\\\\\' "; // 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/