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(`<meta (?:name|http-equiv)='(.*)' content='(.*)'>`) var str = `<meta charset='UTF-8'> <meta name='keywords' content='your, tags'> <meta name='description' content='150 words'> <meta name='subject' content='your website's subject'> <meta name='copyright' content='company name'> <meta name='language' content='ES'> <meta name='robots' content='index,follow'> <meta name='revised' content='Sunday, July 18th, 2010, 5:15 pm'> <meta name='abstract' content=''> <meta name='topic' content=''> <meta name='summary' content=''> <meta name='Classification' content='Business'> <meta name='author' content='name, email@hotmail.com'> <meta name='designer' content=''> <meta name='reply-to' content='email@hotmail.com'> <meta name='owner' content=''> <meta name='url' content='http://www.websiteaddrress.com'> <meta name='identifier-URL' content='http://www.websiteaddress.com'> <meta name='directory' content='submission'> <meta name='pagename' content='jQuery Tools, Tutorials and Resources - O'Reilly Media'> <meta name='category' content=''> <meta name='coverage' content='Worldwide'> <meta name='distribution' content='Global'> <meta name='rating' content='General'> <meta name='revisit-after' content='7 days'> <meta name='subtitle' content='This is my subtitle'> <meta name='target' content='all'> <meta name='HandheldFriendly' content='True'> <meta name='MobileOptimized' content='320'> <meta name='date' content='Sep. 27, 2010'> <meta name='search_date' content='2010-09-27'> <meta name='DC.title' content='Unstoppable Robot Ninja'> <meta name='ResourceLoaderDynamicStyles' content=''> <meta name='medium' content='blog'> <meta name='syndication-source' content='https://mashable.com/2008/12/24/free-brand-monitoring-tools/'> <meta name='original-source' content='https://mashable.com/2008/12/24/free-brand-monitoring-tools/'> <meta name='verify-v1' content='dV1r/ZJJdDEI++fKJ6iDEl6o+TMNtSu0kv18ONeqM0I='> <meta name='y_key' content='1e39c508e0d87750'> <meta name='pageKey' content='guest-home'> <meta itemprop='name' content='jQTouch'> <meta http-equiv='Expires' content='0'> <meta http-equiv='Pragma' content='no-cache'> <meta http-equiv='Cache-Control' content='no-cache'> <meta http-equiv='imagetoolbar' content='no'> <meta http-equiv='x-dns-prefetch-control' content='off'>` 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/