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"
"
gm

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)(^|(?<=\s))\d{8,12}(?=\s|\.|$)`) var str = `e5655558888 r666666 t 5987442510 j69698888885 U 568457562388 11255525h555h4 4444444444444444 5655555/85 55555-555-23-23 55 This next section I do NOT want to be captured 636363666-66-12345678 I56588895620 56854444002 this number can be anywhere in the sentence ike this: 123456789 Or it could just be like this 98765432 these are good but it should NOT find this 050860404-01e0-4a5a-b8db-a97f26a668ac p 63666900000 bank account 12356895555 123456780000 2222 05086040 Not sure what the plan might be thought for when i have a sentence with account information for my checking account written in a document like this, here is the savings account number 1234567890. thank you. overdraft 9876543210` 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/