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Commit 946a981

Browse files
updates for version 2.0
1 parent 6bc20cb commit 946a981

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+1958
-1641
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‎Exercise_solutions.md

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‎Exercises.md

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‎LICENSE

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MIT License
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Copyright (c) 2019 Sundeep Agarwal
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Copyright (c) 2023 Sundeep Agarwal
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal

‎README.md

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# JavaScript RegExp
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# Understanding JavaScript RegExp
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Example based guide to mastering JavaScript regexp.
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Learn JavaScript Regular Expressions step-by-step from beginner to advanced levels with hundreds of examples and exercises. Visit https://youtu.be/8X-hUel3GxM for a short video about the book.
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<p align="center">
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<img src="./images/js_regexp.png" width="320px" height="400px" />
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</p>
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<p align="center"><img src="./images/js_regexp_ls.png" alt="Understanding JavaScript RegExp ebook cover image" /></p>
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The book also includes exercises to test your understanding, which is presented together as a single file in this repo - [Exercises.md](./Exercises.md)
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The book also includes exercises to test your understanding, which are presented together as a single file in this repo — [Exercises.md](./Exercises.md).
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For solutions to the exercises, see [Exercise_solutions.md](./Exercise_solutions.md).
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# E-book
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You can purchase the pdf/epub versions of the book using these links:
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* You can purchase the pdf/epub versions of the book using these links:
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* https://learnbyexample.gumroad.com/l/js_regexp
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* https://leanpub.com/js_regexp
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* You can also get the book as part of these bundles:
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* **All books bundle** bundle from https://learnbyexample.gumroad.com/l/all-books
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* Includes all my programming books
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* **Awesome Regex** bundle from https://learnbyexample.gumroad.com/l/regex or https://leanpub.com/b/regex
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* See https://learnbyexample.github.io/books/ for a list of other books
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* https://learnbyexample.gumroad.com/l/js_regexp
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* https://leanpub.com/js_regexp
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For a preview of the book, see [sample chapters](./sample_chapters/js_regexp_sample.pdf).
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You can also get the book as part of these bundles:
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The book can also be [viewed as a single markdown file in this repo](./js_regexp.md). See my blogpost on [generating pdfs from markdown using pandoc](https://learnbyexample.github.io/customizing-pandoc/) if you are interested in the ebook creation process.
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* **Awesome Regex** bundle from https://learnbyexample.gumroad.com/l/regex or https://leanpub.com/b/regex
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* **All books bundle** bundle from https://learnbyexample.gumroad.com/l/all-books
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* Includes all my programming books
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See https://learnbyexample.github.io/books/ for list of other books
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For a preview of the book, see [sample chapters](https://github.com/learnbyexample/learn_js_regexp/blob/master/sample_chapters/js_regexp_sample.pdf)
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The book can also be [viewed as a single markdown file in this repo](./js_regexp.md). See my blogpost on [generating pdf from markdown using pandoc](https://learnbyexample.github.io/tutorial/ebook-generation/customizing-pandoc/) if you are interested in the ebook creation process.
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For web version of the book, visit https://learnbyexample.github.io/learn_js_regexp/
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For the web version of the book, visit https://learnbyexample.github.io/learn_js_regexp/
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<br>
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# Feedback
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[Open an issue](https://github.com/learnbyexample/learn_js_regexp/issues) if you spot any typo/errors.
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⚠️ ⚠️ Please DO NOT submit pull requests. Main reason being any modification requires changes in multiple places.
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:warning::warning: Please DO NOT submit pull requests. Main reason being any modification requires changes in multiple places.
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I would highly appreciate it if you'd let me know how you felt about this book. It could be anything from a simple thank you, pointing out a typo, mistakes in code snippets, which aspects of the book worked for you (or didn't!) and so on. Reader feedback is essential and especially so for self-published authors.
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I'd also highly appreciate your feedback about the book.
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You can reach me via:
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Twitter: https://twitter.com/learn_byexample
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* Issue Manager: [https://github.com/learnbyexample/learn_js_regexp/issues](https://github.com/learnbyexample/learn_js_regexp/issues)
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* E-mail: `echo 'bGVhcm5ieWV4YW1wbGUubmV0QGdtYWlsLmNvbQo=' | base64 --decode`
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* Twitter: [https://twitter.com/learn_byexample](https://twitter.com/learn_byexample)
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<br>
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# Table of Contents
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1. Preface
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2. What's so special about Regular Expressions?
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2. Why is it needed?
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3. RegExp introduction
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4. Anchors
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5. Alternation and Grouping
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# Acknowledgements
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* [MDN: Regular Expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) — documentation and examples
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* [/r/learnjavascript/](https://www.reddit.com/r/learnjavascript/) and [/r/regex/](https://www.reddit.com/r/regex/) — helpful forums for beginners and experienced programmers alike
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* [MDN: Regular Expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions) — documentation and examples
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* [/r/learnjavascript/](https://old.reddit.com/r/learnjavascript/) and [/r/regex/](https://old.reddit.com/r/regex/) — helpful forums for beginners and experienced programmers alike
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* [stackoverflow](https://stackoverflow.com/) — for getting answers to pertinent questions on JavaScript and regular expressions
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* [tex.stackexchange](https://tex.stackexchange.com/) — for help on [pandoc](https://github.com/jgm/pandoc/) and `tex` related questions
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* Cover image: [LibreOffice Draw](https://www.libreoffice.org/discover/draw/) and [regulex](https://jex.im/regulex)
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* [canva](https://www.canva.com/) — cover image
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* [Warning](https://commons.wikimedia.org/wiki/File:Warning_icon.svg) and [Info](https://commons.wikimedia.org/wiki/File:Info_icon_002.svg) icons by [Amada44](https://commons.wikimedia.org/wiki/User:Amada44) under public domain
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* [pngquant](https://pngquant.org/) and [svgcleaner](https://github.com/RazrFalcon/svgcleaner) for optimizing images
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* [oxipng](https://github.com/shssoichiro/oxipng), [pngquant](https://pngquant.org/) and [svgcleaner](https://github.com/RazrFalcon/svgcleaner) — optimizing images
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* [mdBook](https://github.com/rust-lang/mdBook) — for web version of the book
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* [mdBook-pagetoc](https://github.com/JorelAli/mdBook-pagetoc) — for adding table of contents for each chapter
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* [minify-html](https://github.com/wilsonzlin/minify-html) — for minifying html files
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# License
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The book is licensed under a [Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-nc-sa/4.0/)
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The book is licensed under a [Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-nc-sa/4.0/).
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The code snippets are licensed under MIT, see [LICENSE](./LICENSE) file.
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The code snippets are licensed under MIT, see [LICENSE](./LICENSE) file

‎Version_changes.md

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<br>
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### 2.0
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* Examples and exercises added for `d` and `v` flags
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* Strings in code snippets changed to be uniformly represented in single quotes
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* In general, many of the examples, exercises, solutions, descriptions and external links were updated/corrected
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* Updated Acknowledgements section
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* Code snippets related to info/warning sections will now appear as a single block
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* Book title changed to **Understanding JavaScript RegExp**
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* New cover image
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* Images centered for EPUB format
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<br>
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### 1.6
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* Code snippets checked to work with Chrome/Chromium console version 89+

‎code_snippets/Alternation_and_Grouping.js

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// OR conditional
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// Alternation
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const pets = /cat|dog/
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pets.test('I like parrots')
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'catapults concatenate cat scat'.replace(/^cat|cat\b/g, 'X')
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'catapults concatenate cat scat cater'.replace(/^cat|cat\b/g, 'X')
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'cat dog bee parrot fox'.replace(/cat|dog|fox/g, 'mammal')
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‎code_snippets/Anchors.js

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/er$/m.test('spare\npar\nera\ndare')
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let elements = ['spare\ntool', 'par\n', 'dare', 'spared']
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elements.filter(e => /are$/m.test(e))
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/^par$/m.test('spare\npar\nera\ndare')
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let items = 'catapults\nconcatenate\ncat'
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console.log(items.replace(/$/gm, '.'))
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'1\n2\n'.replace(/^/mg, 'foo ')
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console.log('1\n2\n'.replace(/^/mg, 'fig '))
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'1\n2\n'.replace(/$/mg, ' baz')
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console.log('1\n2\n'.replace(/$/mg, ' apple'))
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// Word anchors
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let sample = 'par spar apparent spare part'
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let words = 'par spar apparent spare part'
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words.replace(/par/g, 'X')
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sample.replace(/par/g, 'X')
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words.replace(/\bpar/g, 'X')
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sample.replace(/\bpar/g, 'X')
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words.replace(/par\b/g, 'X')
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sample.replace(/par\b/g, 'X')
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words.replace(/\bpar\b/g, 'X')
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sample.replace(/\bpar\b/g,'X')
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letwords='par spar apparent spare part'
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letsample='par spar apparent spare part'
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console.log(words.replace(/\b/g,'"').replace(//g,','))
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console.log(sample.replace(/\b/g, '"').replace(//g,','))
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'output=num1+35*42/num2'.replace(/\b/g, ' ')
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'foo_baz=num1+35*42/num2'.replace(/\b/g, ' ')
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'output=num1+35*42/num2'.replace(/\b/g, ' ').trim()
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'foo_baz=num1+35*42/num2'.replace(/\b/g,' ').trim()
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// Opposite Word Anchor
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let sample = 'par spar apparent spare part'
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let words = 'par spar apparent spare part'
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sample.replace(/\Bpar/g, 'X')
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words.replace(/\Bpar/g, 'X')
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sample.replace(/\Bpar\b/g, 'X')
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words.replace(/\Bpar\b/g, 'X')
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sample.replace(/par\B/g, 'X')
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words.replace(/par\B/g, 'X')
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sample.replace(/\Bpar\B/g, 'X')
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words.replace(/\Bpar\B/g, 'X')
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'copper'.replace(/\b/g, ':')
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‎code_snippets/Character_class.js

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// Custom character sets
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['cute', 'cat', 'cot', 'coat', 'cost'].filter(w => /c[ou]t/.test(w))
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['cute', 'cat', 'cot', 'coat', 'cost','scuttle'].filter(w => /c[ou]t/.test(w))
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'meeting cute boat site foot'.replace(/[aeo]+t/g, 'X')
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'Sample123string42with777numbers'.match(/[0123456789]+/g)
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'Sample123string42with777numbers'.match(/[0-9]+/g)
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'coat Bin food tar12 best'.match(/\b[a-z0-9]+\b/g)
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'coat Bin food tar12 best Apple fig_42'.match(/\b[a-z0-9]+\b/g)
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'coat tin food put stoop best'.match(/\b[p-z][a-z]*\b/g)
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'coat tin food put stoop best fig_42 Pet'.match(/\b[p-z][a-z]*\b/g)
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'coat tin food put stoop best'.match(/\b[a-fp-t]+\b/g)
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'coat tin food put stoop best fig_42 Pet'.match(/\b[a-fp-t]+\b/g)
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'Sample123string42with777numbers'.match(/[^0-9]+/g)
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'foo=42; baz=123'.replace(/^[^=]+/, '')
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'foo:123:bar:baz'.replace(/^([^:]+:){2}/, '')
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'apple:123:banana:cherry'.replace(/^([^:]+:){2}/, '')
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'foo=42; baz=123'.replace(/=[^=]+$/, '')
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'apple=42; cherry=123'.replace(/=[^=]+$/, '')
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// Escape sequence sets
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'sea eat car rat eel tea'.match(/\b\w/g).join('')
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'tea sea-pit sit-lean bean'.match(/[\w\s]+/g)
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'tea sea-Pit Sit;(lean_2\tbean_3)'.match(/[\w\s]+/g)
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'Sample123string42with777numbers'.replace(/\D+/g, '-')
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' 1..3 \v\f foo_baz 42\tzzz \r\n1-2-3 '.match(/\S+/g)
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' 1..3 \v\f fig_tea 42\tzzz \r\n1-2-3 '.match(/\S+/g)
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‎code_snippets/Dot_metacharacter_and_Quantifiers.js

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'breadth markedly reported overrides'.replace(/r..d/g, 'X')
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'42\t35'.replace(/2.3/, '8')
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// split method
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'cag̈ed'.replace(/a.e/, 'o')
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'cag̈ed'.replace(/a..e/, 'o')
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// split() method
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'bus:3:car:5:van'.split(/:.:/)
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'bus:3:car:-:van'.split(/:.:/)
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'3111111111125111142'.split(/1+/)
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let demo = ['abc', 'ac', 'abbc', 'xabbbcz', 'bc', 'abbbbbc']
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let repeats = ['abc', 'ac', 'abbc', 'xabbbcz', 'bc', 'abbbbbc']
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repeats.filter(w => /ab{1,4}c/.test(w))
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demo.filter(w => /ab{1,4}c/.test(w))
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repeats.filter(w => /ab{0,2}c/.test(w))
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demo.filter(w => /ab{0,2}c/.test(w))
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repeats.filter(w => /ab{3,}c/.test(w))
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demo.filter(w => /ab{3,}c/.test(w))
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repeats.filter(w => /ab{3}c/.test(w))
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demo.filter(w => /ab{3}c/.test(w))
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'a{5} = 10'.replace(/a\{5}/g, 'a{6}')
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'report_{a,b}.txt'.replace(/_{a,b}/g, '-{c,d}')
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'foot'.replace(/f.?o/, 'X')
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console.log('blah < foo \\< bar < baz'.replace(/\\?</g, '\\<'))
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console.log('table < fig \\< bat < cake'.replace(/\\?</g, '\\<'))
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'hand handy handful'.replace(/hand(y|ful)?/g, 'X')
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'123456789'.replace(/.{2,5}?/, 'X')
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'green:3.14:teal::brown:oh!:blue'.split(/:.*?:/)
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let sentence = 'that is quite a fabricated tale'
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sentence.replace(/t.*?a/, 'X')
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'green:3.14:teal::brown:oh!:blue'.split(/:.*:/)
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'star'.replace(/t.*?a/, 'X')
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sentence.replace(/t.*?a.*?f/, 'X')
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'green:3.14:teal::brown:oh!:blue'.split(/:.*?:/)
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// s flag
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'Hi there\nHave a Nice Day'.replace(/the.*ice/, 'X')
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console.log('Hi there\nHave a Nice Day'.replace(/the.*ice/, 'X'))
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'Hi there\nHave a Nice Day'.replace(/the.*ice/s, 'X')
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console.log('Hi there\nHave a Nice Day'.replace(/the.*ice/s, 'X'))
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‎code_snippets/Escaping_metacharacters.js

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// Escaping with \
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'cater cat concatenate par spare'.replace(p4, 'X')
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// Escaping delimiter
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// Escaping the delimiter
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let path = '/abc/123/foo/baz/ip.txt'
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let path = '/home/joe/report/sales/ip.txt'
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path.replace(/^\/abc\/123\//, '~/')
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path.replace(/^\/home\/joe\//, '~/')
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path.replace(new RegExp(`^/abc/123/`), '~/')
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path.replace(new RegExp(`^/home/joe/`), '~/')
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// Escape sequences
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