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

/
/
gx

Test String

Code Generator

Language

Generated Code

use strict; my $str = 'LKHS>APRS,TCPIP*,qAC,GLIDERN2:/211635h4902.45NI01429.51E&000/000/A=001689 v0.2.4.ARM CPU:0.2 RAM:777.7/972.2MB NTP:3.1ms/-3.8ppm +33.6C RF:+62-0.8ppm/+33.66dB Moosburg>APRS,TCPIP*,qAC,GLIDERN1:/232205h4827.52NI01155.89E&000/000/A=001397 v0.2.4.ARM CPU:0.8 RAM:788.7/1017.6MB NTP:16000.0ms/-73.4ppm RF:+8.00dB'; my $regex = qr/(?<callsign>\w+?)>APRS,.+?, (?<receiver>\w+):\/ (?<time>\d{6})h (?<latitude>\d{4}\.\d{2}[NS]). (?<longitude>\d{5}\.\d{2}[EW]). (?:(?<heading>\d{3})\/(?<ground_speed>\d{3}))?.*? \/A=(?<altitude>\d{6})\s (?:!W((?<latitude_enhancement>\d)(?<longitude_enhancement>\d))!)? (?:v(?<version>\d+\.\d+\.\d+)(?:\.(?<platform>.+?))?\s)? CPU:(?<cpu_load>[\d.]+)\s RAM:(?<ram_free>[\d.]+)\/(?<ram_total>[\d.]+)MB\s NTP:(?<ntp_offset>[\d.]+)ms\/(?<ntp_correction>[+-][\d.]+)ppm\s? (?:(?<cpu_temperature>[+-][\d.]+)C\s*)? (?:RF: (?: (?<manual_correction>[+-][\d]+) (?<automatic_correction>[+-][\d.]+)ppm\/ )? (?<signal>[+-][\d.]+)dB )?/xp; if ( $str =~ /$regex/g ) { 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