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

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)\b(?:https?:\/\/)?[\w-\.$~!&'()*+,;=:%-]{3,50}:([\w-\.%$^#&'()*+,;=:%-]{3,50})@[a-zA-Z0-9.-]+(?:\.[a-zA-Z]{2,})?\b`) var str = `### rgmz example @----__-2as-2:password@----__-2as-2.com ### From test cases var ( validPattern = " https://kaNydBSAodo87dSAFtsd7.com:1234@qYY3SylY7fHP " validPattern2 = \`<p><a href="http://username:password@127.0.0.1">http://username:password@127.0.0.1</a></p>\` invalidPattern = "https://kaNydBSAodo87dsm9asuiSAFtsd7.com.1234@qYY3SylY7fHP" keyword = "uri" ) ### examples from chatgpt 1. \`https://user.name:pa$$word123@sub.example.com\` 2. \`http://u$er_name:my%p@$$word@api.dev.localhost\` 3. \`https://12345:67890@my-app.server123.co.uk\` 4. \`http://user~!name:pass.word@some-long-subdomain.example.org\` 5. \`https://_:__@localhost\` 6. \`https://admin:admin123@192.168.1.1\` 7. \`http://test-user:complex!password#123@server.example.io\` 8. \`https://valid_user:!valid-password@simple-host.co\` 9. \`http://username_with.dots:password_with-dashes@domain.with.subdomain.net\` 10. \`https://username:password@127.0.0.1:8080\` 11. \`http://user:pass@----__-2as-2\` 12. \`https://user@localhost\` 13. \`http://user:pass@:invalidhost\` 14. \`https://:passwordonly@hostname.com\` 15. \`ftp://username:password@hostname.com\` 16. \`https://user:password@hostname_with_underscores.com\` 17. \`http://user@:missingpassword.com\` 18. \`https://missingcolonpassword@hostname.com\` 19. \`http://user:password@-invalid-hostname.com\` 20. \`https://user:password@host..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/