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

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)(?:^(?:[^\n\r]+)(?:\r?\n|$))+`) var str = `e|---------------------------------|------------------------------------| e|------------------------------------------------------------------| B|-----1--------(1)----1-----------|-------1---------------1----------1-| B|-----1--------(1)----0---------0-----1---------1-----3--------(3)-| G|-----------0------------0--------|-------------0----------------0-----| G|-----------0---------------0---------------0---------------0------| D|-----0h2-----2-------2-----------|-------2-------2-------0--------0---| D|-----2-------2-------2-------2-------2-------2-------0-------0----| A|-3-------3-------3-------3-------|------------------------------------| A|-0-------0--------------------------------------------------------| E|-----------------------------0---|---1-------1-------3-------3--------| E|-----------------0-------0--------1------1-------3-------3--------| e|-------------------------------------------------------------------| B|-----1---------1-----1---------1-----3---------3-------1---------1-| G|-----------0---------------0---------------0-----------------0-----| D|-----3-------2-------2-------2-------0-------0---------2-------2---| A|-----------------3-------3-------------------------3-------3-------| E|-1-------1-----------------------3-------3-------------------------|` 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/