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

/
/
s

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?s)<a.*?href=\"(.+.pdf\?min)\".*?>(.*?)<\/a>`) var str = []byte(`<table cellspacing="0" cellpadding="0" width="100%" border="0"> <tbody> <tr> <td width="25%"><a href="http://www.test.com/myfile.pdf?min" target="_blank">Menus 18 €</a></div></td> <td width="25%"><a href="http://www.test.com/myfile.pdf?min" target="_blank">Menus 24 et 26 €</a></div></td> <td width="25%"><a href="http://www.test.com/myfile.pdf?min" target="_blank">Menus 30 et 37 € </a></div></td> <td width="25%"><a href="http://www.test.com/myfile.pdf?min">La Carte détaillée&nbsp;<br> (Entrées - Viandes - Poissons)</a></td> </tr> </tbody> </table>`) var substitution = []byte("ok") var count = 1 // negative counter is equivalent to global case (replace all) str = re.ReplaceAllStringFunc(str, func(s string) string { if count == 0 { return s } count -= 1 return re.ReplaceAllString(s, substitution) }) fmt.Println(string(str)) }

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/