Regular Expressions 101

Save & Share

  • Regex Version: ver. 2
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8
  • .NET 7.0 (C#)
  • Rust
  • Regex Flavor Guide

Function

  • Match
  • Substitution
  • List
  • Unit Tests

Tools

Sponsors
There are currently no sponsors. Become a sponsor today!
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

/
/
mg

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)^s?([\/|@#])(?:(?!\1).)+\1(?:(?!\1).)*\1(?:i|(?:gi?|ig)(\1\d{1,2})?)?$ `) var str = `should match: /.// |.|| s/.// /.//g /.//i /././gi /one-or-more/anything/ /one-or-more/anything/g/3 /one-or-more/anything/i /one-or-more/anything/gi/99 s/one-or-more/anything/g/4 s/one-or-more/anything/i s/one-or-more/anything/gi/54 s|.|| |.||g |.||i |.|.|gi |one-or-more|anything| |one-or-more|anything|g|3 |one-or-more|anything|i |one-or-more|anything|gi|99 s|one-or-more|anything|g|4 s|one-or-more|anything|i s|one-or-more|anything|gi|54 should not match: s/one-or-more/anything/33 s|one-or-more|anything|33 /./ |.| s|one-or-more|anything|gi|3333 s/one-or-more/anything/gi/3333 /./// s/./// s/./.// /anything/anything/anything/anything/ s/anything/anything/anything/ s/anything/anything/anything/g s/anything/anything/anything/i s/anything/anything/anything/gi /anything/anything/anything/gi /anything/anything/anything/g /anything/anything/anything/i |.||| s|.||| s|.|.|| |anything|anything|anything|anything| s|anything|anything|anything| s|anything|anything|anything|g s|anything|anything|anything|i s|anything|anything|anything|gi |anything|anything|anything|gi |anything|anything|anything|g |anything|anything|anything|i` 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/