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 single character of: a, b, c or d
    [[ab][cd]]
  • 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]
  • Character class intersection
    [\w&&[^\d]]
  • 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

"
"
s

Test String

Code Generator

Language

Generated Code

use strict; my $str = '2016-06-22 00:00:15,759 [http-nio-8110-exec-12] ERROR com.encima.project.h2y.handlers.XML.XMLBusinessComparator - [Tx: 710117088] Hotel id 10500 : No weekends found for given hotel with the query criteria QueryData(arrivaldate=2016-09-05, nbofnights=6, nbofadults=2, nbofchildren=0, agechildren=null, nbofbabies=0, agebabies=null, nbofrooms=1, language=es, affiliate=4894, hotelIds=[10628, 12175, 9869, 12905, 11670, 10500, 10822, 12132, 6309, 12559])'; my $regex = qr/(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2},\d{3}) \[.*\] ERROR com.encima.project.h2y.handlers.XML.XMLBusinessComparator - \[Tx: (\d{8,12})\] Hotel id (\d*) : No weekends found for given hotel with the query criteria QueryData\(arrivaldate=(\d{4}-\d{2}-\d{2}), nbofnights=(\d), nbofadults=(\d), nbofchildren=(\d), agechildren=.{0,4}, nbofbabies=\d, agebabies=.{0,4}, nbofrooms=(\d), language=(\w{2}), affiliate=(\d{0,5}), hotelIds=.*/sp; if ( $str =~ /$regex/ ) { print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n"; # print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n"; # print "Capture Group 2 is $2 ... and so on\n"; } # ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p' # Named capture groups can be called via $+{name}

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 Perl, please visit: http://perldoc.perl.org/perlre.html