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"dcs.lustre.device.ost.attributes\[.*-((.*).+?),.*,rate\]").unwrap(); let string = "[ { itemid: \"26940\", status: \"0\", lastvalue: \"60843699081216\", lastclock: \"1454321651\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0000,kbytesavail]\", name: \"OST0000 available space\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"60\", value_type: \"3\", units: \"Bytes\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26943\", status: \"0\", lastvalue: \"61486384615424\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0001,kbytesfree]\", name: \"OST0001 free space\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26944\", status: \"0\", lastvalue: \"62068190941184\", lastclock: \"1454272094\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0000,kbytestotal]\", name: \"OST0000 total space\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"86400\", value_type: \"3\", units: \"Bytes\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26945\", status: \"0\", lastvalue: \"62068190941184\", lastclock: \"1454272092\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0001,kbytestotal]\", name: \"OST0001 total space\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"86400\", value_type: \"3\", units: \"Bytes\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26946\", status: \"0\", lastvalue: \"0\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0000,read_bytes,rate]\", name: \"OST0000 read\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes/sec\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26942\", status: \"0\", lastvalue: \"61477895307264\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0000,kbytesfree]\", name: \"OST0000 free space\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26951\", status: \"0\", lastvalue: \"2878341087\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0001,write_bytes,rate]\", name: \"OST0001 write\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes/sec\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26950\", status: \"0\", lastvalue: \"3185573852\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0000,write_bytes,rate]\", name: \"OST0000 write\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes/sec\", category: \"performance\", type: \"filesystem\", history: \"90\" }, { itemid: \"26947\", status: \"0\", lastvalue: \"0\", lastclock: \"1454321686\", key_: \"dcs.lustre.device.ost.attributes[plexfs-OST0001,read_bytes,rate]\", name: \"OST0001 read\", hostname: \"lustre_plexfs\", value: \"lustre\", delay: \"5\", value_type: \"3\", units: \"Bytes/sec\", category: \"performance\", type: \"filesystem\", history: \"90\" } ]"; // 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/