Regular Expressions 101

Save & Share

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

`
`
gm

Test String

Code Generator

Language

Generated Code

package main import ( "regexp" "fmt" ) func main() { var re = regexp.MustCompile(`(?m)^\s+(?P<user>[\w[:print:]]+) [\w\-\.]+ [[:print:]]+ ?\(v[\w\.]+\) \([\w\-\.]+\/\d+ \d+\)\, start \w+ \d+\/\d+ \d+\:\d+(\,\s(?P<licenses>\d+)\s\w+|)(\s+\(linger\:\s\d+\s\/\s\d+\))?$`) var str = ` userone host01 :78 APS Base (v19.100) (licserver/27010 7401), start Thu 5/14 15:31, 2 licenses userone host01 :78 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 7501), start Thu 5/14 15:31, 4 licenses userone host01 :75 APS Base (v19.100) (licserver/27010 18901), start Thu 5/14 15:33, 2 licenses userone host01 :75 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 19001), start Thu 5/14 15:33, 4 licenses userone host01 :76 APS Base (v19.100) (licserver/27010 18702), start Thu 5/14 15:34, 2 licenses userone host01 :76 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 17002), start Thu 5/14 15:34, 4 licenses userone host01 :77 APS Base (v19.100) (licserver/27010 23302), start Thu 5/14 15:34, 2 licenses userone host01 :77 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 23801), start Thu 5/14 15:34, 4 licenses userone host01 :60 APS Base (v19.100) (licserver/27010 23901), start Thu 5/14 15:34, 2 licenses userone host01 :60 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 24001), start Thu 5/14 15:34, 4 licenses userone host01 :68 APS Base (v19.100) (licserver/27010 25501), start Thu 5/14 15:34, 2 licenses userone host01 :68 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 25601), start Thu 5/14 15:34, 4 licenses userone host01 :58 APS Base (v19.100) (licserver/27010 22803), start Thu 5/14 15:34, 2 licenses userone host01 :58 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 27801), start Thu 5/14 15:34, 4 licenses useronexr host01 :51 Spectre X Base (v19.100) (licserver/27010 61140), start Sat 5/16 13:41, 3 licenses useronexr host01 :52 Spectre X Base (v19.100) (licserver/27010 31125), start Sat 5/16 13:43, 3 licenses useronexr host01 :76 Spectre X Base (v19.100) (licserver/27010 53463), start Sat 5/16 13:47, 3 licenses useronexr host01 :69 Spectre X Base (v19.100) (licserver/27010 41523), start Sat 5/16 13:47, 3 licenses useronexr host01 :51 Spectre X Multi-core (Max. 16 cores) (v19.100) (licserver/27010 46233), start Sat 5/16 14:08, 6 licenses useronex host01 :52 Spectre X Multi-core (Max. 16 cores) (v19.100) (licserver/27010 32328), start Sat 5/16 14:10, 6 licenses useronex host01 :69 Spectre X Multi-core (Max. 16 cores) (v19.100) (licserver/27010 10953), start Sat 5/16 14:16, 6 licenses useronex host02 :76 Spectre X Multi-core (Max. 16 cores) (v19.100) (licserver/27010 32114), start Sat 5/16 14:17, 6 licenses useronexr host02 localhost:10 APS Base (v19.100) (licserver/27010 31935), start Sun 5/17 10:18, 2 licenses useronexr host02 localhost:10 APS Multi-core (Max. 16 cores) (v19.100) (licserver/27010 6614), start Sun 5/17 10:21, 4 licenses ` 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/