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

%
%
gm

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)<a[\s\S]*? \bhref="(mailto:(.*?))"[\s\S]*?>(.*?)</a>`) var str = `<p>Lorem ipsum dolor sit amet, <a href="#coucou">consectetur </a> dipiscing elit. <a href="mailto:fakeEmail@gmail.com">Email Tag Content 1</a>.Sic enim censent, oportunitatis esse beate vivere. Omnia contraria, quos etiam insanos esse vultis. Virtutis, magnitudinis animi, patientiae, fortitudinis fomentis dolor mitigari solet. <a href="mailto:email@address.uk">Quid</a>, cum fictas fabulas, e quibus utilitas nulla elici potest, cum voluptate legimus? Duo Reges: <a href="mailto:tt@tt.com" class="asdkfj">constructio</a> interrete. Vos autem cum perspicuis dubia debeatis illustrare, dubiis perspicua conamini tollere. Quid ad utilitatem <a class="t" href="mailto:aaa@uuu.ik">tantae</a> pecuniae? Quod non subducta utilitatis ratione effici solet, sed ipsum a se oritur et sua sponte nascitur.` 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/