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

/
/

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`((19\d\d|20\d\d)-(0\d|1[0-2])-([0-2]\d|30|31))T((\d{2}):(\d{2}):(\d{2}))(?:\.(\d{3,6}))?(?:((?:([+-])(?:(0\d|1[012]))):?([0-5]\d))|Z?)`) var str = `2008 2004-04-14 1997-01-27T18:57Z 2010-14-21T08:12:17.243+07:00 2010-12-21T08:12:17.243Z 2010-12-21T08:12:17.243 2010-11-21T08:12:17.243+07:00 2010-11-01T08:12:17.243+07:00 2010-12-11T08:12:17.243+0700 2010-01-21T08:12:17.243+07:00 2010-11-31T08:12:17.243+07:00 2010-14-21T08:12:17.243-37:00 2010-11-32T08:12:17.243+07:00 2010-14-21T08:12:17.243+0000 2010-14-21T08:12:17.243+1000 2010-11-21T08:12:17.243+0060 2010-14-21T08:12:17.243+1000 2010-14-21T08:12:17.243+1000 Non-Matches 3:00, 2/28/2003 2004-07-12 14:25:59 1900-01-01 00:00:00 9999-12-31 23:59:59 Non-Matches 04-07-12 14:25:59 20004-07-12 14:25 2004/07/12 14:25:59` if len(re.FindStringIndex(str)) > 0 { fmt.Println(re.FindString(str),"found at index",re.FindStringIndex(str)[0]) } }

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/