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

r"
"

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`/*.mkv`) var str = `folder.jpg metadata Stargate SG-1 S01E01-E02 Children of the Gods.mkv Stargate SG-1 S01E03 The Enemy Within.mkv Stargate SG-1 S01E04 Emancipation.mkv Stargate SG-1 S01E05 The Broca Divide.mkv Stargate SG-1 S01E06 The First Commandment.mkv Stargate SG-1 S01E07 Cold Lazarus.mkv Stargate SG-1 S01E08 The Nox.mkv Stargate SG-1 S01E09 Brief Candle.mkv Stargate SG-1 S01E10 Thor's Hammer.mkv Stargate SG-1 S01E11 The Torment of Tantalus.mkv Stargate SG-1 S01E12 Bloodlines.mkv Stargate SG-1 S01E13 Fire and Water.mkv Stargate SG-1 S01E14 Hathor.mkv Stargate SG-1 S01E15 Singularity.mkv Stargate SG-1 S01E16 Cor-Ai.mkv Stargate SG-1 S01E17 Enigma.mkv Stargate SG-1 S01E18 Solitudes.mkv Stargate SG-1 S01E19 Tin Man.mkv Stargate SG-1 S01E20 There But For the Grace of God.mkv Stargate SG-1 S01E21 Politics (1).mkv Stargate SG-1 S01E22 Within the Serpent's Grasp (2).mkv ` if len(re.FindStringIndex(str)) > 0 { fmt.Println(re.FindString(str),"found at index",re.FindStringIndex(str)[0]) } }

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/