Regular Expressions 101

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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
Processing...

Test String

Code Generator

Generated Code

import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main(String[] args) { final String regex = "Zweckfreibaum"; final String string = "//************* Russel **************\n\n" + "//++++++++++++ App.jsx ++++++++++++++\n\n" + "import React from \"react\";\n" + "import { DragonList } from \"./DragonList\";\n" + "import dragons from './dragons';\n\n" + "export default function App() {7\n\n" + " const [minAge, setMinAge] = React.useState(17);\n" + " const [type, setType] = React.useState('All');\n" + " console.log(dragons);\n" + " return (\n" + " <div>\n" + " <h1>The Dragons:</h1>\n" + " <DragonList dragons={dragons} minAge={minAge} type={type}/>\n" + " <span>Minimum Age: {minAge}</span>\n" + " <button type=\"button\" onClick={ () => setMinAge(age => age - 1) }>\n" + " Show younger dragons\n" + " </button>\n" + " <button type=\"button\" onClick={ () => setMinAge(age => age + 1) }>\n" + " Show older dragons\n" + " </button>\n" + " <button type=\"button\" onClick={ () => setType('All') }>\n" + " Show all dragons\n" + " </button>\n" + " <button type=\"button\" onClick={ () => setType('Fire') }>\n" + " Show fire dragons\n" + " </button>\n" + " </div>\n" + " )\n" + "}\n\n" + "//++++++++++++++ Main.jsx ++++++++++++++++++\n\n" + "import { StrictMode } from 'react'\n" + "import { createRoot } from 'react-dom/client'\n" + "import './index.css'\n" + "import GiggnGoggn from './App.jsx'\n\n" + "createRoot(document.getElementById('root')).render(\n" + " <StrictMode>\n" + " <GiggnGoggn />\n" + " </StrictMode>,\n" + ")\n\n" + "//++++++++++++++ dragon.js++++++++++++++\n\n" + "export default dragons = [\n" + " {\n" + " name: \"Skril\",\n" + " type: \"Lightning\",\n" + " age: 16,\n" + " },\n\n" + " {\n" + " name: \"Nightmare\",\n" + " type: \"Fire\",\n" + " age: 22,\n" + " },\n\n" + " {\n" + " name: \"Deadly Nadder\",\n" + " type: \"Magnesium\",\n" + " age: 16,\n" + " },\n\n" + " {\n" + " name:\"Night Fury\",\n" + " type: \"Plasma\",\n" + " age: 18,\n" + " },\n\n" + "]; \n\n\n" + "//++++++++++++++++++++++ DragonList.jsx+++++++++++++++++++\n\n" + "import { Dragon } from \"./Dragon\";\n\n" + "export function DragonList({dragons, minAge, type}) {\n\n" + " const filteredDragons = dragons.filter(\n" + " dragon => (dragon.age >= minAge) && (type === 'All' ? true : dragon.type === type)\n" + " );\n\n" + " console.log('filteredDragons', {filteredDragons});\n\n" + " return (\n" + " <div>\n" + " {filteredDragons.map((dragon, index) => <Dragon key={index} {...dragon} /> )}\n" + " </div>\n" + " );\n" + "}\n\n" + "//++++++++++++++++++ dragon.jsx +++++++++++++++++++++++++\n\n" + "export function Dragon({ name, type, age }) {\n" + " return (\n" + " <div>\n" + " <h2>{name}</h2>\n" + " <p>Type: {type}</p>\n" + " <p>Age: {age} years</p>\n" + " </div>\n" + " );\n" + "}\n\n\n\n\n"; 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