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

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "<div\\sid=\\\"[\\s\\S]*?dp_productDescription_container_div[\\s\\S]*?<div\\sid=\\\"productDescription_feature_div[\\s\\S]*?<div[\\s\\S]*?<div[\\s\\S]*?<div\\sid=\\\"productDescription[\\s\\S]*?>([\\s\\S]*?<p>[\\s\\S]*?<\\/p>\\s*)<\\/div>"; final String string = "<div id=\"dp_productDescription_container_div\" class=\"feature\" data-feature-name=\"productDescription\" data-cel-widget=\"dp_productDescription_container_div\">\n" + " \n" + " \n\n\n\n\n" + " \n\n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n\n\n\n" + " \n" + " <div id=\"productDescription_feature_div\" data-feature-name=\"productDescription\" data-template-name=\"productDescription\" class=\"a-row feature\" data-cel-widget=\"productDescription_feature_div\">\n" + " \n" + " \n" + " \n" + " <div class=\"a-divider a-divider-section\"><div class=\"a-divider-inner\"></div></div>\n" + " \n" + " \n" + " <h2 class=\"softlines\">\n" + " Product description\n" + " \n" + " </h2>\n" + " \n" + " \n" + " \n\n" + " \n" + " \n" + " \n" + " \n" + " \n\n\n\n\n\n" + " <div id=\"productDescription\" class=\"a-section a-spacing-small\">\n" + " \n\n\n\n\n\n" + " \n" + " \n" + " \n\n\n" + " \n" + " \n" + " \n" + " \n" + " \n\n" + " \n" + " \n" + " \n" + " \n" + " \n" + " <!-- show up to 2 reviews by default --> \n" + " \n" + " \n" + " \n" + " \n" + " <p>Train better. Look great. The Vazee agility trainer supports your interval workouts with an exciting blend of fashionable colors and a newly designed performance lace mesh upper for support and breathability.\n" + " \n" + " </p>\n" + " \n" + " \n" + " <p>Train better. Look great. The Vazee agility trainer supports your interval workouts with an exciting blend of fashionable colors and a newly designed performance lace mesh upper for support and breathability.\n" + " \n" + " </p> \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " </div>\n\n" + " \n" + " <style type=\"text/css\">\n" + "#productDescription {\n" + " color: #333333;\n" + " word-wrap: break-word;\n" + " font-size: small;\n" + " line-height: initial;\n" + " margin: 0.5em 0px 0em 25px;\n" + "}\n\n" + "#productDescription_feature_div > h2.default {\n" + " color: #CC6600;\n" + " font-size: medium;\n" + " margin: 0 0 0.25em;\n" + "}\n\n" + "#productDescription_feature_div > h2.books {\n" + " color:#333 !important;\n" + " font-size:21px !important;\n" + " line-height: 1.3;\n" + " padding-bottom: 4px;\n" + " font-weight: normal;\n" + " margin: 0px;\n" + "}\n\n" + "#productDescription_feature_div > h2.softlines {\n" + " color:#333 !important; \n" + " font-size:21px !important;\n" + " line-height: 1.3;\n" + " padding-bottom: 4px;\n" + " font-weight: bold;\n" + " margin: 0px;\n" + "}\n" + "#productDescription > p, #productDescription > div, #productDescription > table {\n" + " margin: 0 0 1em 0;\n" + "}\n\n" + "#productDescription p {\n" + " margin: 0em 0 1em 1em;\n" + "}\n\n" + "#productDescription h3 {\n" + " font-weight: normal;\n" + " color: #333333;\n" + " font-size: 1.23em;\n" + " clear: left;\n" + " margin: 0.75em 0px 0.375em -15px;\n" + "}\n\n" + "#productDescription table {\n" + " border-collapse: inherit !important;\n" + " margin-bottom: 0;\n" + "}\n\n" + "#productDescription table img {\n" + " max-width: inherit !important;\n" + "}\n\n" + "#productDescription table td {\n" + " font-size: small;\n" + " vertical-align: inherit !important;\n" + "}\n\n" + "#productDescription ul li {\n" + " margin: 0 0 0 20px;\n" + "}\n\n" + "#productDescription ul li ul {\n" + " list-style-type: disc !important;\n" + " margin-left: 20px !important;\n" + "}\n\n" + "#productDescription ul ul li {\n" + " list-style-type: disc !important;\n" + " margin-left: 20px !important;\n" + "}\n\n" + "#productDescription > ul ul li {\n" + " list-style-type: disc !important;\n" + "} \n\n\n" + "#productDescription ul li ul li {\n" + " margin: 0 0 0 20px;\n" + "}\n\n" + "#productDescription .aplus p {\n" + " margin: 0 0 1em 0;\n" + "}\n\n" + "#productDescription small {\n" + " font-size: smaller;\n" + "}\n\n" + "#productDescription.prodDescWidth {\n" + " max-width: 1000px\n" + "}\n\n" + "</style>\n\n" + "<!-- Used to set table width because AUI is overriding the width attribute of the tables coming in description -->\n" + "<script type=\"text/javascript\">\n" + "P.when('jQuery').execute(function($){\n" + " $(\"#productDescription table\").each(function() {\n" + " var width = $(this).attr('width');\n" + " if (width) width += 'px';\n" + " else width = 'auto';\n" + " $(this).css('width', width);\n\n" + " var padding = $(this).attr('cellpadding');\n" + " if (padding) padding += 'px';\n" + " else padding = '0px';\n" + " $(this).css('padding', padding);\n" + " });\n" + "});\n" + "</script>\n\n" + " \n\n\n\n" + " \n" + " \n" + " \n" + " \n" + " </div>\n\n\n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n" + " \n\n" + " \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n" + " </div>"; final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE); final Matcher matcher = pattern.matcher(string); while (matcher.find()) { System.out.println("Full match: " + matcher.group(0)); for (int i = 1; i <= matcher.groupCount(); i++) { System.out.println("Group " + i + ": " + matcher.group(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 Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html