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

/
/
gimx

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?im)^( \#[\da-f]{3} |\#[\da-f]{6} |rgba\( ((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*,\s*){2} ((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*) (,\s*(0\.\d+|1)) \) |hsla\( \s*((\d{1,2}|[1-2]\d{2}|3([0-5]\d|60)))\s*, \s*((\d{1,2}|100)\s*%)\s*, \s*((\d{1,2}|100)\s*%) (,\s*(0\.\d+|1)) \) |rgb\( ((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*,\s*){2} ((\d{1,2}|1\d\d|2([0-4]\d|5[0-5]))\s*) \) |hsl\( \s*((\d{1,2}|[1-2]\d{2}|3([0-5]\d|60)))\s*, \s*((\d{1,2}|100)\s*%)\s*, \s*((\d{1,2}|100)\s*%) \) )$`) var str = `#ffffff #nothing #AF12AA rgba(222, 222, 222) RgBa(72,73,75) hsl(0, 100%, 100%) rgba(1024, 1024, 10) #ffffff #ffffffasdf asdf#ffffff rgba(170,221,255,0.59) rgba(170,221,255,0.59)asdf rgb(0, 0, 0) asdfrgb(0, 0, 0) rgb(0, 0, 0)asdf hsla(208, 56%, 46%, 1) hsla(208, 56%, 46%, 1)asdf asdfhsla(208, 56%, 46%, 1) hsl(208,56%,46%)asdf asdfhsl(208,56%,46%)` 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/