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.*?data-extra-url=".*?<\/a>`) var str = `<div> <br> <a data-some-id="3-6-9;id-1-2-3" data-more-id="1-3-5" data-extra-url="https://somehost.api/sub-id-1-2-3?someparam=3-6-9;id-1-2-3" href="https://somehost.api/sub-id-1-2-3?someparam=3-6-9;id-1-2-3" class="some-class">someDuplicateHere1</a></div> wysiwyg<br> <div><a class="popup-wrap-id-1-2-3" href="https://somehost.api/app/id-1-2-3?someparam=sub-id-1-2-3;sub-sub-id-1-2-3">firstImage</a></div> <br> <div>somecontent</div> <div> <span> <div><a data-some-id="456;789" href="https://somehost.api/app/id-4-5-6?someparam=sub-id-4-5-6;sub-sub-1-2-3">second</a></div> <br> </span> also some more content </div> <div> <span> <div><a data-some-id="3-6-9;id-1-2-3" data-more-id="1-3-5" data-extra-url="https://somehost.api/app/sub-id-1-2-3?someparam=3-6-9;id-1-2-3" href="https://somehost.api/app/sub-id-1-2-3?someparam=3-6-9;id-1-2-3" class="some-class">someDuplicateHere</a></div> rtf<br> </span> <br> </div> </div>` 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/