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"
"
gm

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)^(Mozilla/5\.0 (\(Linux; Android 6.0.1; Nexus 5X Build/MMB29P\) )?(AppleWebKit/[0-9]+\.[0-9]+ \(KHTML, like Gecko[\);] )?(Chrome/[0-9]{2,3}\.[0-9]+\.[0-9]+\.[0-9]+ Mobile Safari/[0-9]+\.[0-9]+ )?\(?compatible; )?Googlebot((-Image|-Video)?/[0-9]\.[0-9]|-News)(;? \(?\+http://www\.google\.com/bot\.html\)( Chrome/[0-9]{2,3}\.[0-9]+\.[0-9]+\.[0-9]+ Safari/[0-9]+\.[0-9]+)?)?$ `) var str = `Valid GoogleBots: Googlebot-Image/1.0 Googlebot-News Googlebot-Video/1.0 Googlebot/2.1 (+http://www.google.com/bot.html) Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) Chrome/80.20.123.1243 Safari/537.36 Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2213.123 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) Invalid GoogleBots: Googlebot googlebot/2.1 Googlebot/2.1 (+http://www.google.com/bot.html) +IKAUE ` 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/