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)(?<=\"text\": \")(.*?hello.*?)(?=", \"type\": \"text\")"#).unwrap(); let string = "{\"root\": {\"type\": \"root\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"type\": \"paragraph\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"mode\": \"normal\", \"text\": \"text1 hello text\", \"type\": \"text\", \"style\": \"\", \"detail\": 0, \"format\": 0, \"version\": 1}], \"direction\": \"ltr\"}], \"direction\": \"ltr\"}} hellocat world f {\"root\": {\"type\": \"root\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"type\": \"paragraph\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"src\": \"https://images.unsplash.com/photo-1458966480358-a0ac42de0a7a?crop=entropy&cs=tinysrgb&fit=max&fm=jpg&ixid=M3w1MjU5NTl8MHwxfHNlYXJjaHwzfHx0cmVlfGVufDB8fHx8MTcxMzk5MjE4OHww&ixlib=rb-4.0.3&q=80&w=1080\", \"type\": \"image\", \"width\": 332, \"height\": \"221.329875\", \"version\": 1, \"alt_text\": \"image\", \"max_width\": 500}, {\"mode\": \"normal\", \"text\": \"dsadsa\", \"type\": \"text\", \"style\": \"\", \"detail\": 0, \"format\": 0, \"version\": 1}], \"direction\": \"ltr\"}, {\"type\": \"paragraph\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"mode\": \"normal\", \"text\": \"fdsfds\", \"type\": \"text\", \"style\": \"\", \"detail\": 0, \"format\": 0, \"version\": 1}], \"direction\": \"ltr\"}], \"direction\": \"ltr\"}} {\"root\": {\"type\": \"root\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"type\": \"paragraph\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"mode\": \"normal\", \"text\": \"nccccchello ddddd\", \"type\": \"text\", \"style\": \"\", \"detail\": 0, \"format\": 0, \"version\": 1}], \"direction\": \"ltr\"}], \"direction\": \"ltr\"}} {\"root\": {\"type\": \"root\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"tag\": null, \"type\": \"paragraph\", \"start\": null, \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"rel\": null, \"src\": null, \"url\": null, \"mode\": \"normal\", \"text\": \"bvcbvc\", \"type\": \"text\", \"style\": \"\", \"title\": null, \"value\": null, \"width\": null, \"detail\": 0, \"format\": 0, \"height\": null, \"indent\": null, \"inline\": null, \"target\": null, \"checked\": null, \"version\": 1, \"alt_text\": null, \"children\": null, \"equation\": null, \"field_id\": null, \"direction\": null, \"max_width\": null, \"field_name\": null, \"field_type\": null, \"highlight_type\": null, \"hidden_field_name\": null, \"hidden_field_value\": null}], \"language\": null, \"video_id\": null, \"direction\": \"ltr\", \"list_type\": null}], \"direction\": \"ltr\"}} {\"root\": {\"type\": \"root\", \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"tag\": null, \"type\": \"paragraph\", \"start\": null, \"format\": \"\", \"indent\": 0, \"version\": 1, \"children\": [{\"rel\": null, \"src\": null, \"url\": null, \"mode\": \"normal\", \"text\": \"gbfbvc\", \"type\": \"text\", \"style\": \"\", \"title\": null, \"value\": null, \"width\": null, \"detail\": 0, \"format\": 0, \"height\": null, \"indent\": null, \"inline\": null, \"target\": null, \"checked\": null, \"version\": 1, \"alt_text\": null, \"children\": null, \"equation\": null, \"field_id\": null, \"direction\": null, \"max_width\": null, \"field_name\": null, \"field_type\": null, \"highlight_type\": null, \"hidden_field_name\": null, \"hidden_field_value\": null}], \"language\": null, \"video_id\": null, \"direction\": \"ltr\", \"list_type\": null}], \"direction\": \"ltr\"}}"; // 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/