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"
"
gsi

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?si)(.*?)\n+http://[^\n]*`) var str = `Switch To Webmail   Forward As Attachment   Subject:   Happy Halloween! Save 20% off Your Customer Pick Order of $35+ & Get Free Shipping From:   "Steve Clayton, Inc." <questions@steveclayton.com>; Date:   CSUS : 2019-10-21 13:58:45       CSUK : 2019-10-21 21:58:45       CSAU : 2019-10-22 07:58:45       CSCA : 2019-10-21 16:58:45   To:   alondra.lord@soarinfotech.com; Greetings! http://r20.rs6.net/tn.jsp?f=0014SGOrR3ASe9IyglfygZLXfHhrRAmkPn-73YbC2ynwMJ7PkFvp390uIy0yJCAN-mY1b-EkfryOvw5p9xfNsi4kjE2XQIXO3TMsMcUAVBvR12dZBb_uXVkIhiHjo-OwkYriobWoXY34X5wKNqE0g89LpSq1mz4yPT-0QUl6--2Sx_1zzmq_y2DxA==&c=FxWRjueN1esWXtTd5CiUManoqQSCzYeeNCYetAu6uISMrHXQi5jT_A==&ch=bfhpEqDHS21OhVfblebShZJCqsmks2YfZgG5E4G9rML4gixyTZXiQQ== Steve Clayton, Inc., 201 Rogue River Parkway, Talent, OR 97540 http://ui.constantcontact.com/sa/fwtf.jsp?llr=oimxtpcab&m=1102183117070&ea=chrystal%40steveclayton.com&a=1133410274742 Forward email | https://visitor.constantcontact.com/do?p=oo&m=001qFmiWSczCnpJ0RpvJUB4sw%3D%3D&ch=9adda1e0-441c-11e9-ad0b-d4ae5292c4dd&ca=1c3a31d6-0436-4a39-b723-ecf6b602376e Update Profile | http://www.constantcontact.com/legal/service-provider?cc=about-service-provider About our service provider Sent by mailto:questions@steveclayton.com questions@steveclayton.com "` 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/