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

/
/
gmi

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?mi)(?!(?!.*?<a)[^<]*<\/a>)(?<!")(?:(?:https?|ftp|file):\/\/|www\.|ftp\.|youtube\.|youtu\.be)[\-A-Z0-9\+\&\#\/%=~_|$?!:;,\.]*[A-Z0-9+&#\/%=~_|$]`) var str = `youtu.be/iwGFalTRHDA youtube.com/watch?v=iwGFalTRHDA www.youtube.com/watch?v=iwGFalTRHDA http://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=MoBL33GT9S8&feature=share https://www.youtube.com/embed/watch?feature=player_embedded&v=iwGFalTRHDA https://www.youtube.com/embed/watch?v=iwGFalTRHDA https://www.youtube.com/embed/v=iwGFalTRHDA https://www.youtube.com/watch/iwGFalTRHDA http://www.youtube.com/attribution_link?u=/watch?v=aGmiw_rrNxk&feature=share https://m.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=DFYRQ_zQ-gk&feature=featured https://www.youtube.com/watch?v=DFYRQ_zQ-gk http://www.youtube.com/watch?v=DFYRQ_zQ-gk //www.youtube.com/watch?v=DFYRQ_zQ-gk www.youtube.com/watch?v=DFYRQ_zQ-gk https://youtube.com/watch?v=DFYRQ_zQ-gk http://youtube.com/watch?v=DFYRQ_zQ-gk //youtube.com/watch?v=DFYRQ_zQ-gk youtube.com/watch?v=DFYRQ_zQ-gk https://m.youtube.com/watch?v=DFYRQ_zQ-gk http://m.youtube.com/watch?v=DFYRQ_zQ-gk //m.youtube.com/watch?v=DFYRQ_zQ-gk m.youtube.com/watch?v=DFYRQ_zQ-gk https://www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US http://www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US //www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US https://www.youtube.com/embed/DFYRQ_zQ-gk?autoplay=1 https://www.youtube.com/embed/DFYRQ_zQ-gk http://www.youtube.com/embed/DFYRQ_zQ-gk //www.youtube.com/embed/DFYRQ_zQ-gk www.youtube.com/embed/DFYRQ_zQ-gk https://youtube.com/embed/DFYRQ_zQ-gk http://youtube.com/embed/DFYRQ_zQ-gk //youtube.com/embed/DFYRQ_zQ-gk youtube.com/embed/DFYRQ_zQ-gk https://youtu.be/DFYRQ_zQ-gk?t=120 https://youtu.be/DFYRQ_zQ-gk http://youtu.be/DFYRQ_zQ-gk //youtu.be/DFYRQ_zQ-gk youtu.be/DFYRQ_zQ-gk https://www.youtube.com/HamdiKickProduction?v=DFYRQ_zQ-gk "https://youtu.be/yVpbFMhOAwE", "https://www.youtube.com/embed/yVpbFMhOAwE", "youtu.be/yVpbFMhOAwE", "youtube.com/watch?v=yVpbFMhOAwE", "http://youtu.be/yVpbFMhOAwE&t=2m", "http://www.youtube.com/embed/yVpbFMhOAwE&t=2m5s", "http://www.youtube.com/watch?v=yVpbFMhOAwE", "http://www.youtube.com/watch?v=yVpbFMhOAwE&feature=g-vrec&t=30s", "http://www.youtube.com/watch?v=yVpbFMhOAwE&feature=player_embedded", "http://www.youtube.com/v/yVpbFMhOAwE?fs=1&hl=en_US", "http://www.youtube.com/ytscreeningroom?v=yVpbFMhOAwE", "http://www.youtube.com/watch?NR=1&feature=endscreen&v=yVpbFMhOAwE", "http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo", "http://www.youtube.com/watch?v=6zUVS4kJtrA&feature=c4-overview-vl&list=PLbzoR-pLrL6qucl8-lOnzvhFc2UM1tcZA", "https://www.youtube.com/watch?v=FZu097wb8wU&list=RDFZu097wb8wU" youtu.be/iwGFalTRHDA youtube.com/watch?v=iwGFalTRHDA www.youtube.com/watch?v=iwGFalTRHDA http://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=MoBL33GT9S8&feature=share https://www.youtube.com/embed/watch?feature=player_embedded&v=iwGFalTRHDA https://www.youtube.com/embed/watch?v=iwGFalTRHDA https://www.youtube.com/embed/v=iwGFalTRHDA https://www.youtube.com/watch/iwGFalTRHDA http://www.youtube.com/attribution_link?u=/watch?v=aGmiw_rrNxk&feature=share https://m.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=DFYRQ_zQ-gk&feature=featured https://www.youtube.com/watch?v=DFYRQ_zQ-gk http://www.youtube.com/watch?v=DFYRQ_zQ-gk //www.youtube.com/watch?v=DFYRQ_zQ-gk www.youtube.com/watch?v=DFYRQ_zQ-gk https://youtube.com/watch?v=DFYRQ_zQ-gk http://youtube.com/watch?v=DFYRQ_zQ-gk //youtube.com/watch?v=DFYRQ_zQ-gk youtube.com/watch?v=DFYRQ_zQ-gk https://m.youtube.com/watch?v=DFYRQ_zQ-gk http://m.youtube.com/watch?v=DFYRQ_zQ-gk //m.youtube.com/watch?v=DFYRQ_zQ-gk m.youtube.com/watch?v=DFYRQ_zQ-gk https://www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US http://www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US //www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US www.youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US youtube.com/v/DFYRQ_zQ-gk?fs=1&hl=en_US https://www.youtube.com/embed/DFYRQ_zQ-gk?autoplay=1 https://www.youtube.com/embed/DFYRQ_zQ-gk http://www.youtube.com/embed/DFYRQ_zQ-gk //www.youtube.com/embed/DFYRQ_zQ-gk www.youtube.com/embed/DFYRQ_zQ-gk https://youtube.com/embed/DFYRQ_zQ-gk http://youtube.com/embed/DFYRQ_zQ-gk //youtube.com/embed/DFYRQ_zQ-gk youtube.com/embed/DFYRQ_zQ-gk https://www.youtube-nocookie.com/embed/DFYRQ_zQ-gk?autoplay=1 https://youtu.be/DFYRQ_zQ-gk?t=120 https://youtu.be/DFYRQ_zQ-gk http://youtu.be/DFYRQ_zQ-gk //youtu.be/DFYRQ_zQ-gk youtu.be/DFYRQ_zQ-gk https://www.youtube.com/HamdiKickProduction?v=DFYRQ_zQ-gk https://www.youtube.com/feed/subscriptions https://www.youtube.com/channel/UCgc00bfF_PvO_2AvqJZHXFg https://www.youtube.com/c/NatGeoEdOrg/videos youtu.be/iwGFalTRHDA youtube.com/watch?v=iwGFalTRHDA www.youtube.com/watch?v=iwGFalTRHDA http://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=iwGFalTRHDA https://www.youtube.com/watch?v=MoBL33GT9S8&feature=share https://www.youtube.com/embed/watch?feature=player_embedded&v=iwGFalTRHDA https://www.youtube.com/embed/watch?v=iwGFalTRHDA https://www.youtube.com/embed/v=iwGFalTRHDA https://www.youtube.com/watch/iwGFalTRHDA http://www.youtube.com/attribution_link?u=/watch?v=aGmiw_rrNxk&feature=share https://m.youtube.com/watch?v=iwGFalTRHDA` var substitution = "<a href="$0">$0</a>" fmt.Println(re.ReplaceAllString(str, substitution)) }

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/