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

/
/
g

Test String

Substitution

Processing...

Code Generator

Language

Generated Code

use strict; my $str = 'part1.htm">MiniTOC</a><a class="toc1" part2.htm">2/5/18, 4549 PM part3.htm">2/7/18, 4516 PM part4.htm">2/15/18, 2557 PM part5.htm">2/20/18, 2507 PM part6.htm">2/21/18, 3502 PM part7.htm">2/21/18, 5506 PM part8.htm">2/22/18, 10503 AM part9.htm">2/22/18, 1543 PM part10.htm">2/27/18, 3514 PM part11.htm">2/28/18, 2533 PM part12.htm">3/1/18, 1515 PM part13.htm">3/1/18, 2527 PM part14.htm">3/1/18, 6547 PM part15.htm">3/1/18, 8557 PM part16.htm">3/4/18, 11540 AM part17.htm">3/5/18, 4546 PM part18.htm">3/6/18, 12548 PM part19.htm">3/6/18, 2518 PM part20.htm">3/7/18, 12535 PM part21.htm">3/8/18, 8500 AM part22.htm">3/8/18, 10521 AM part23.htm">3/8/18, 12559 PM part24.htm">3/9/18, 10540 AM part25.htm">3/9/18, 1501 PM part26.htm">3/9/18, 6514 PM part27.htm">3/12/18, 8514 PM part28.htm">3/14/18, 12520 PM part29.htm">3/14/18, 2537 PM part30.htm">3/15/18, 2514 PM part31.htm">3/15/18, 3549 PM part32.htm">3/21/18, 11506 AM part33.htm">3/22/18, 2518 PM part34.htm">3/22/18, 3523 PM part35.htm">3/22/18, 4554 PM part36.htm">3/26/18, 3543 PM part37.htm">4/2/18, 1555 PM part38.htm">4/2/18, 4532 PM part39.htm">4/5/18, 1557 PM part40.htm">4/6/18, 4536 PM part41.htm">4/6/18, 5540 PM part42.htm">4/6/18, 7501 PM part43.htm">4/7/18, 5524 AM part44.htm">4/16/18, 12525 PM part45.htm">4/17/18, 4502 PM part46.htm">4/23/18, 7520 PM part47.htm">4/25/18, 3527 PM part48.htm">4/25/18, 5513 PM part49.htm">4/26/18, 2534 PM part50.htm">4/26/18, 6513 PM part51.htm">5/1/18, 3523 PM part52.htm">5/3/18, 3540 PM part53.htm">5/4/18, 12539 PM part54.htm">5/8/18, 12539 PM part55.htm">5/8/18, 2549 PM part56.htm">5/9/18, 12506 PM part57.htm">5/15/18, 3525 PM part58.htm">5/23/18, 6545 PM part59.htm">5/24/18, 2559 PM part60.htm">5/24/18, 5523 PM part61.htm">5/26/18, 3509 PM part62.htm">5/27/18, 11519 AM part63.htm">5/30/18, 4554 PM part64.htm">5/26/18, 1507 PM part65.htm">5/31/18, 2558 PM part66.htm">6/7/18, 2546 PM part67.htm">6/11/18, 7531 PM part68.htm">6/12/18, 10547 AM part69.htm">6/12/18, 3529 PM part70.htm">6/13/18, 7536 PM part71.htm">6/14/18, 3527 PM part72.htm">6/19/18, 8507 AM part73.htm">6/19/18, 3528 PM part74.htm">6/19/18, 5519 PM part75.htm">6/20/18, 10507 AM part76.htm">6/21/18, 10545 AM part77.htm">6/21/18, 12544 PM part78.htm">6/21/18, 3534 PM part79.htm">6/23/18, 11506 AM part80.htm">6/23/18, 3505 PM part81.htm">6/23/18, 6500 PM part82.htm">6/24/18, 10535 AM part83.htm">6/24/18, 12556 PM part84.htm">6/25/18, 7517 PM part85.htm">6/26/18, 3517 PM part86.htm">6/26/18, 4559 PM part87.htm">6/27/18, 9551 AM </a><a class="toc1" part88.htm">6/27/18, 11532 AM part89.htm">6/28/18, 4515 PM </a><a class="toc1" part90.htm">7/2/18, 6529 PM part91.htm">7/3/18, 3554 PM part92.htm">7/3/18, 5545 PM part93.htm">7/3/18, 7556 PM part94.htm">7/3/18, 9503 PM part95.htm">7/7/18, 5531 PM part96.htm">7/9/18, 4553 PM part97.htm">7/10/18, 8554 AM part98.htm">7/10/18, 5516 PM part99.htm">7/11/18, 11531 AM part100.htm">7/11/18, 3550 PM part101.htm">7/12/18, 4549 PM part102.htm">7/15/18, 3524 PM part103.htm">7/16/18, 10525 AM part104.htm">7/16/18, 11534 AM part105.htm">7/16/18, 6544 PM part106.htm">7/18/18, 11505 AM part107.htm">7/19/18, 1537 PM part108.htm">7/19/18, 3532 PM part109.htm">7/24/18, 10500 AM part110.htm">7/24/18, 2514 PM part111.htm">7/24/18, 3555 PM part112.htm">7/24/18, 7506 PM part113.htm">8/9/18, 12537 PM part114.htm">8/13/18, 3531 PM part115.htm">8/13/18, 5551 PM part116.htm">8/14/18, 12509 PM part117.htm">8/14/18, 1532 PM part118.htm">8/14/18, 3539 PM part119.htm">8/16/18, 4548 PM part120.htm">8/16/18, 4548 PM part121.htm">8/21/18, 6509 PM part122.htm">8/23/18, 11557 AM part123.htm">8/28/18, 4537 PM part124.htm">8/30/18, 7528 PM part125.htm">8/30/18, 10500 PM part126.htm">9/4/18, 2538 PM part127.htm">9/4/18, 5515 PM part128.htm">9/5/18, 3538 PM part129.htm">9/7/18, 5519 PM part130.htm">9/10/18, 3518 PM part131.htm">9/13/18, 8541 AM part132.htm">9/13/18, 11512 AM part133.htm">9/13/18, 12551 PM part134.htm">9/17/18, 6502 PM part135.htm">9/18/18, 3555 PM part136.htm">9/19/18, 9506 PM part137.htm">9/19/18, 11504 PM part138.htm">9/20/18, 12531 PM part139.htm">9/24/18, 4502 PM part140.htm">9/24/18, 6518 PM part141.htm">9/25/18, 9550 AM part142.htm">9/25/18, 5512 PM part143.htm">9/26/18, 12549 PM part144.htm">9/26/18, 6533 PM part145.htm">9/28/18, 9543 AM part146.htm">10/1/18, 7558 AM part147.htm">10/1/18, 3538 PM part148.htm">10/3/18, 10551 AM part149.htm">10/3/18, 3521 PM part150.htm">10/3/18, 4528 PM part151.htm">10/3/18, 5529 PM part152.htm">10/8/18, 11521 AM part153.htm">10/8/18, 2526 PM part154.htm">10/8/18, 4538 PM part155.htm">10/9/18, 1504 PM part156.htm">10/9/18, 4529 PM part157.htm">10/9/18, 6552 PM part158.htm">10/10/18, 6509 PM part159.htm">10/11/18, 1544 PM part160.htm">10/11/18, 3527 PM part161.htm">10/11/18, 5552 PM part162.htm">10/11/18, 8500 PM part163.htm">10/16/18, 2515 PM part164.htm">10/16/18, 4501 PM part165.htm">10/18/18, 10541 AM part166.htm">10/18/18, 1505 PM part167.htm">10/18/18, 4524 PM part168.htm">10/18/18, 7537 PM part169.htm">10/19/18, 11532 AM part170.htm">10/22/18, 9539 AM part171.htm">10/22/18, 10543 AM part172.htm">10/22/18, 12514 PM part173.htm">10/22/18, 2523 PM part174.htm">10/24/18, 10506 AM part175.htm">10/24/18, 12535 PM part176.htm">10/24/18, 5558 PM part177.htm">11/1/18, 3525 PM part178.htm">11/1/18, 3525 PM part179.htm">11/5/18, 11509 AM part180.htm">11/5/18, 1544 PM part181.htm">11/8/18, 6521 PM part182.htm">11/9/18, 11538 AM part183.htm">11/10/18, 11525 AM part184.htm">11/10/18, 2531 PM part185.htm">11/14/18, 10530 AM part186.htm">11/14/18, 2505 PM part187.htm">11/14/18, 4521 PM part188.htm">11/14/18, 5527 PM part189.htm">11/15/18, 11541 AM part190.htm">11/15/18, 12558 PM part191.htm">11/18/18, 8559 PM part192.htm">11/19/18, 11502 AM part193.htm">11/19/18, 12512 PM part194.htm">11/26/18, 12537 PM part195.htm"> 11/27/18, 3535 PM part196.htm">11/28/18, 9535 AM part197.htm">11/28/18, 12551 PM part198.htm">11/29/18, 11541 AM part199.htm">12/3/18, 11512 AM part200.htm">12/3/18, 4501 PM part201.htm">12/4/18, 12510 PM part202.htm">12/4/18, 2504 PM part203.htm">12/4/18, 3559 PM part204.htm">12/7/18, 11548 AM part205.htm">12/7/18, 1542 PM part206.htm">12/10/18, 12521 PM part207.htm">12/11/18, 12518 PM part208.htm">12/14/18, 9517 AM part209.htm">12/14/18, 11554 AM part210.htm">12/14/18, 1547 PM part211.htm">12/14/18, 3530 PM part212.htm">12/14/18, 9531 PM part213.htm">12/16/18, 6506 PM part214.htm">12/17/18, 11556 AM part215.htm">12/19/18, 4500 PM part216.htm">12/20/18, 2558 PM part217.htm">12/20/18, 7516 PM part218.htm">12/21/18, 4516 PM part219.htm">12/21/18, 7510 PM part220.htm">12/25/18, 10518 PM part221.htm">1/1/19, 10540 AM part222.htm">1/1/19, 3521 PM part223.htm">1/3/19, 6501 PM part224.htm">1/4/19, 11540 AM part225.htm">1/4/19, 2501 PM part226.htm">1/4/19, 3555 PM part227.htm">1/6/19, 2519 PM part228.htm">1/7/19, 9531 AM part229.htm">1/7/19, 11527 AM part230.htm">1/7/19, 9532 PM part231.htm">1/8/19, 10534 PM part232.htm">1/9/19, 1512 PM part233.htm">1/10/19, 9551 AM part234.htm">1/10/19, 5537 PM part235.htm">1/11/19, 12526 PM part236.htm">1/14/19, 12522 PM part237.htm">1/13/19, 6555 PM part238.htm">1/11/19, 1557 PM part239.htm">1/17/19, 9539 AM part240.htm">1/17/19, 3513 PM part241.htm">1/18/19, 1505 PM part242.htm">1/18/19, 2549 PM part243.htm">1/22/19, 9557 AM part244.htm">1/22/19, 3530 PM part245.htm">1/24/19, 12532 PM part246.htm">1/24/19, 2554 PM part247.htm">1/25/19, 2554 PM part248.htm">1/29/19, 9552 AM part249.htm">1/30/19, 8528 AM part250.htm">1/30/19, 11550 AM part251.htm">2/1/19, 9506 AM part252.htm">2/1/19, 11529 AM part253.htm">2/1/19, 12557 PM part254.htm">2/1/19, 4522 PM part255.htm">2/2/19, 8519 AM part256.htm">2/5/19, 1500 PM part257.htm">2/5/19, 3537 PM part258.htm">2/7/19, 2534 PM part259.htm">2/8/19, 3526 PM part260.htm">2/8/19, 5510 PM part261.htm">2/11/19, 4538 PM part262.htm">2/12/19, 10555 AM part263.htm">2/13/19, 2514 PM part264.htm">2/13/19, 4533 PM part265.htm">2/13/19, 8537 PM part266.htm">2/14/19, 8544 AM part267.htm">2/14/19, 10516 AM part268.htm">2/14/19, 11543 AM part269.htm">2/16/19, 2501 PM part270.htm">2/16/19, 3541 PM part271.htm">2/19/19, 7501 PM part272.htm">2/20/19, 10526 AM part273.htm">2/20/19, 12501 PM part274.htm">2/20/19, 4534 PM part275.htm">2/24/19, 10550 AM part276.htm">2/24/19, 12506 PM part277.htm">2/24/19, 12506 PM part278.htm">2/25/19, 1541 PM part279.htm">2/25/19, 4554 PM part280.htm">2/28/19, 2522 PM part281.htm">3/6/19, 12522 PM part282.htm">3/7/19, 12522 PM part283.htm">3/7/19, 4517 PM part284.htm">3/8/19, 2534 PM part285.htm">3/12/19, 7514 PM part286.htm">3/13/19, 11546 AM part287.htm">3/13/19, 12552 PM part288.htm">3/14/19, 2502 PM part289.htm">3/15/19, 12545 PM part290.htm">3/15/19, 4553 PM part291.htm">3/18/19, 10522 AM part292.htm">3/18/19, 11544 AM part293.htm">3/18/19, 2536 PM part294.htm">3/18/19, 4513 PM part295.htm">3/19/19, 10506 AM part296.htm">3/19/19, 1543 PM part297.htm">3/20/19, 10530 AM part298.htm">3/24/19, 11516 AM part299.htm">3/24/19, 1533 PM part300.htm">3/26/19, 8530 AM part301.htm">3/28/19, 9507 PM part302.htm">3/29/19, 8523 AM part303.htm">4/2/19, 10504 AM part304.htm">4/2/19, 11534 AM part305.htm">4/2/19, 1508 PM '; my $regex = qr/( \d{1,2})5(\d{2} )/p; my $subst = '\\1:\\2'; my $result = $str =~ s/$regex/$subst/rg; print "The result of the substitution is' $result\n";

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