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

/
/
mg

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)^(?<name>.*)time:\s*\[(?<low>\d+\.?\d*)\s(?:\w{1,2})\s(?<value>\d+\.?\d*)\s(?<unit>\w{1,2})\s(?<high>\d+\.?\d*).*$`) var str = `Symbol Creation time: [567.19 us 572.98 us 580.80 us] Found 17 outliers among 100 measurements (17.00%) 4 (4.00%) high mild 13 (13.00%) high severe Running target/release/deps/fib-9ff430dbccaab995 Benchmarking fibonacci (Execution): Warming up for 3.0000 s fibonacci (Execution) time: [5.4756 ms 5.5354 ms 5.6049 ms] Found 13 outliers among 100 measurements (13.00%) 3 (3.00%) high mild 10 (10.00%) high severe Running target/release/deps/string-21e60149b4b73866 Hello World (Execution) time: [518.17 us 519.92 us 521.89 us] Found 12 outliers among 100 measurements (12.00%) 7 (7.00%) high mild 5 (5.00%) high severe Hello World (Lexer) time: [1.8861 us 1.9440 us 2.0071 us] change: [+13.420% +15.685% +17.802%] (p = 0.00 < 0.05) Performance has regressed. Found 2 outliers among 100 measurements (2.00%) 1 (1.00%) high mild 1 (1.00%) high severe ` for i, match := range re.FindAllString(str, -1) { fmt.Println(match, "found at index", i) } }

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 Golang, please visit: https://golang.org/pkg/regexp/