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

/
/
g

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?:(.{2,})\1)`) var str = `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` 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/