Regular Expressions 101

Save & Share

  • Regex Version: ver. 2
  • Update Regex
    ctrl+⇧+s
  • Save new Regex
    ctrl+s
  • Add to Community Library

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

/
/
gs

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 = "\\[\\@if(not)?:([a-zA-Z0-9]+)(?:=(.*?))?\\].*?\\[\\@endif:\\2\\]"; final String string = "<!-- <h1>[!WLANSettings]</h1> -->\n" + "[@if:examplevar=notgiven]this text won't show[@endif:examplevar]\n" + "[@if:wlanena]\n" + "[@if:wlanauto]\n" + "<table id=\"wlanavail\" class=\"colorrows inputtable\">\n" + " <tr id=\"firstrow\">\n" + " <th width=\"30px\"></th>\n" + " <th width=\"240px\">[!Name] (SSID)</th>\n" + " <th width=\"110px\">[!Encryption]</th>\n" + " <th width=\"150px\">[!SignalStrength]</th>\n" + " <th width=\"200px\">[!MAC]</th>\n" + " </tr>\n\n" + " <tr id=\"loadingrow\">\n" + " <td colspan=5 class=\"centertext\"><img src=\"resources/loading.gif\"\n" + " id=\"loadingWlanScan\"></td>\n" + " </tr>\n" + " <tr>\n" + " <td></td>\n" + " <td colspan=4><input type=\"button\" id=\"rescan\"\n" + " value=\"[!Refresh]\" style=\"width: 200px\"></td>\n" + " </tr>\n" + "</table>\n" + "<p></p>\n" + "[@endif:wlanauto]\n" + "<table id=\"wlansettings\" class=\"inputTable\">\n" + " <tr id=\"wlannamerow\" [@if:wlanauto]style=\"display: none;\"[@endif:wlanauto]>\n" + " <td>[!WLANName]</td>\n" + " <td><input type=\"text\" name=\"wlanname\" id=\"wlanname\"\n" + " [@if:wlanauto]value=\"[@wlanname]\"[@endif:wlanauto] style=\"width: 309px;\"></td>\n" + " </tr>\n" + " <tr>\n" + " <td>[!Password]:</td>\n" + " <td><input type=\"text\" name=\"wlanpass\" id=\"wlanpass\"\n" + " style=\"width: 309px;\"></td>\n" + " </tr>\n" + " <tr>\n" + " <td colspan=\"2\" >\n" + " <input type=\"button\" \n" + " [@if:wlanauto]id=\"manualcfg\" name=\"manualcfg\" value=\"[!ManualConfig]\"[@endif:wlanauto]\n" + " [@ifnot:wlanauto]id=\"autocfg\" name=\"autocfg\" value=\"[!AutomaticConfig]\"[@endif:wlanauto]\n" + " onclick=\"handleMultiform(event, this);\" style=\"width: 180px;\">\n" + " </td>\n" + " </tr>\n" + " <tr>\n" + " <td>\n" + " <input type=\"hidden\" name=\"encinput\" id=\"encinput\" value=\"\"></td>\n" + " <td id=\"wlaninfo\"></td>\n" + " </tr>\n" + "</table>\n" + "[@ipsettings]\n\n" + "[@endif:wlanena]\n" + "[@ifnot:wlanena]\n" + "[!NoWLANDevicePluggedIn]\n" + "<p>\n" + " <input type=\"button\" name=\"back\" onclick=\"handleMultiform(event, this);\" value=\"[!Back]\" />\n" + "</p>\n" + "[@endif:wlanena]\n"; final Pattern pattern = Pattern.compile(regex, Pattern.DOTALL); 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