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"
"

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`^([A-PR-UWYZa-pr-uwyz]([0-9]{1,2}|([A-HK-Ya-hk-y][0-9]|[A-HK-Ya-hk-y][0-9]([0-9]|[ABEHMNPRV-Yabehmnprv-y]))|[0-9][A-HJKS-UWa-hjks-uw])\ {0,1}[0-9][ABD-HJLNP-UW-Zabd-hjlnp-uw-z]{2}|([Gg][Ii][Rr]\ 0[Aa][Aa])|([Ss][Aa][Nn]\ {0,1}[Tt][Aa]1)|([Bb][Ff][Pp][Oo]\ {0,1}([Cc]\/[Oo]\ )?[0-9]{1,4})|(([Aa][Ss][Cc][Nn]|[Bb][Bb][Nn][Dd]|[BFSbfs][Ii][Qq][Qq]|[Pp][Cc][Rr][Nn]|[Ss][Tt][Hh][Ll]|[Tt][Dd][Cc][Uu]|[Tt][Kk][Cc][Aa])\ {0,1}1[Zz][Zz]))$`) var str = `AA99 9AA` 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/