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(`^(?<date>\d{4}\-\d{2}\-\d{2})\s+(?<time>\d{2}\:\d{2}\:\d{2})\s+(?<sip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+(?<csmethod>GET|POST|PUT|PATCH|DELETE)\s+(?<csuristem>.+?)\s+(?<csuriquery>.+?)\s+(?<sport>\d{1,3})\s+(.+?)\s+(?<cip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s+(?<csUseragent>.+?)\s+(?<scstatus>\d{1,3})\s+(?<scsubstatus>\d{1,3})\s+(?<scwin32status>\d+)\s+(?<scbytes>\d+)\s+(?<csbytes>\d+)\s+(?<timetaken>\d+)?$`) var str = `2014-05-06 10:27:17 10.200.40.56 GET / - 443 - 10.200.28.7 Mozilla/5.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+WOW64;+Trident/5.0) 401 2 2148074254 1880 428 109` 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/