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)(?i)(?=(\d)\d\d([\s\-\x{2013}\x{2014}\/]))(?<![\d\-\x{2013}\x{2014}%])(?!000|666|9\d\d|\1{3}.\1{2}.\1{4}?|012.34.5678|123.45.6789|234.56.7890|098.76.5432|876.54.3210|078.05.1120|219.09.9999)\d{3}\2(?!00)\d{2}\2(?!0000)\d{4}(?![\d\-\x{2013}\x{2014}%])(?!\.(?:pdf|docx?|xlsx?|pptx?|zip|jpe?g|png|txt|log)\b)`) var str = `################ ## Must match: ################ 123-45-4891 098-18-6564 123-45-4848 702-02-0202 001-14-0004 009 95 8881 123-45-4891 is my ssn my ssn is 123-45-4891 my ssn is 123-45-4891 ok? my ssn is 123-45-4891. 123454891 is my ssn 123 45 4891 is my ssn my ssn is 123 45 4891 my ssn is 123 45 4891 ok? my ssn is 123 45 4891. my ssn is:123-45-4891. my ssn is:123 45 4891. my ssn is:123454891. ss#123-45-4891 ssn123-45-4891 # Space separator: 123 45 4891 # Emdash separator: 123–45–4891 # Endash separator: 123—45—4891 # Slash separator 123/45/4891 ################ ## Must not match: ################ # Unformatted SSN: 009958881 my ssn is 123454891 my ssn is 123454891 ok? my ssn is 123454891. # All-Zero sequence 231-84-0000 231-00-7289 000-87-7289 231 84 0000 231 00 7289 000 87 7289 # Starting with 9 908-78-0485 908 78 0485 # Starting with 666 666-78-0485 # Same number sequences: 222-22-2222 555-55-5555 # Ascending/Descending sequences: 123-45-6789 876-54-321 # Known invalidated SSN: 219-09-9999 078-05-1120 # File names with common extensions: 123-45-4891.pdf 123-45-4891.xlsx Check the attachment: 123-45-4891.xls, then get back to me. Check the attachment: 123-45-4891.jpeg, then get back to me. # Extra digits: 1123-45-4891 123-45-48911 # Unsupported boundaries: –123-45-4891 —123-45-4891 %123-45-4891 123-45-4891- 123-45-4891— 123-45-4891% 1-123-45-4891 123-45-4891-1 # Telephone 1-234-567-8901 1-234-567-8901 1-234-567-8901 1 (234) 567-8901 12347658901 # Credit card 5500 0000 0000 0004 3400 0000 0000 009 3000 0000 0000 04 5500-1244-2232-0004 3400-1244-0000-009 3000-1244-1234-04 # Random Numbers 1234567890112371298739872891738912738937289d712897381297381927d3128937893d7218947d1892742189duc89789v127c897412987893c12893c79 122-426-389 187-5-43212 187-0-43212 2423-45-6789 ` 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/