--- title: "#regex articles | Hashnode" description: "Explore 386 articles tagged #regex on Hashnode. Tutorials, guides, and how-tos from the community." url: "https://hashnode.com/tag/regex" --- Tag # #regex 386 posts · 19 followers [Min SiThu](https://hashnode.com/@itsmeminsithu) · [2h ago](https://hashnode.com/posts/what-is-a-regular-expression-the-little-pattern-that-finds-any-text/6af5134bc550da447638661b) ### [What Is a Regular Expression? The Little Pattern That Finds Any Text](https://itsmeminsithu.hashnode.dev/what-is-a-regular-expression-the-little-pattern-that-finds-any-text?utm_source=hashnode&utm_medium=feed) It looks like keyboard soup, but it is really just a stencil you hold over a page 7 min read · [itsmeminsithu.hashnode.dev](https://itsmeminsithu.hashnode.dev/what-is-a-regular-expression-the-little-pattern-that-finds-any-text?utm_source=hashnode&utm_medium=feed) [Asfaq Leeon](https://hashnode.com/@leeonscoding) · [22h ago](https://hashnode.com/posts/postgresql-string-manipulation-pattern-matching-a-practitioner-s-cheat-sheet/6af3f82ef1eb8bd2a3a54c57) ### [PostgreSQL String Manipulation & Pattern Matching: A Practitioner's Cheat Sheet](https://leeonscoding.hashnode.dev/postgresql-string-manipulation-pattern-matching-a-practitioner-s-cheat-sheet?utm_source=hashnode&utm_medium=feed) You already know SELECT. This is the string toolbox I reach for daily when cleaning, parsing and reshaping text in Postgres, with the gotchas that actually bite in production. One schema, one dataset, 9 min read · [leeonscoding.hashnode.dev](https://leeonscoding.hashnode.dev/postgresql-string-manipulation-pattern-matching-a-practitioner-s-cheat-sheet?utm_source=hashnode&utm_medium=feed) [Emir Mrkaljevic](https://hashnode.com/@emirmrkaljevic) · [1d ago](https://hashnode.com/posts/how-4-becher-125-g-breaks-price-per-kg-math/6af3401ff3630cd9b2fb7331) ### [How "4 Becher à 125 g" breaks price-per-kg math](https://emirmrkaljevic.hashnode.dev/how-4-becher-125-g-breaks-price-per-kg-math?utm_source=hashnode&utm_medium=feed) On a German grocery page, a yogurt is labelled "4 Becher à 125 g". The pack costs €1.99. If you treat that as 125 g, you get €15.92 per kg. The real pack is 500 g, so the price is €3.98 per kg. That i 2 min read · [emirmrkaljevic.hashnode.dev](https://emirmrkaljevic.hashnode.dev/how-4-becher-125-g-breaks-price-per-kg-math?utm_source=hashnode&utm_medium=feed) [VASP Tracker](https://hashnode.com/@vasptracker) · [2d ago](https://hashnode.com/posts/hong-kong-s-misleading-names-test-as-code-what-a-table-a-table-b-matcher-can-and-can-t-tell-you/6af27f7ae173da6a9f05c1a9) ### [Hong Kong's "misleading names" test as code: what a Table A × Table B matcher can and can't tell you](https://vasptracker.hashnode.dev/hong-kong-s-misleading-names-test-as-code-what-a-table-a-table-b-matcher-can-and-can-t-tell-you?utm_source=hashnode&utm_medium=feed) The SFC's 6 November 2026 conclusions give two word lists and a "closely resembles" clause. I built the obvious screener, ran it against real names, and wrote down where it breaks. 8 min read · [vasptracker.hashnode.dev](https://vasptracker.hashnode.dev/hong-kong-s-misleading-names-test-as-code-what-a-table-a-table-b-matcher-can-and-can-t-tell-you?utm_source=hashnode&utm_medium=feed) [Syed Salman](https://hashnode.com/@syedsalman-a2z) · [Oct 29](https://hashnode.com/posts/how-to-run-a-user-s-regex-without-letting-it-freeze-the-browser-tab/6ae3a6976ec829459e02d2af) ### [How to run a user's regex without letting it freeze the browser tab](https://a2ztools.hashnode.dev/how-to-run-a-user-s-regex-without-letting-it-freeze-the-browser-tab?utm_source=hashnode&utm_medium=feed) If your page lets people type a regular expression and run it, one bad pattern can lock the whole tab. JavaScript's RegExp engine backtracks, so a pattern like this one /^(a+)+$/ against "aaaaaaaaaaa 4 min read · [a2ztools.hashnode.dev](https://a2ztools.hashnode.dev/how-to-run-a-user-s-regex-without-letting-it-freeze-the-browser-tab?utm_source=hashnode&utm_medium=feed) [Miller Elias](https://hashnode.com/@eliasmiller) · [Oct 16](https://hashnode.com/posts/demystifying-regular-expressions-from-nfa-backtracking-and-redos-to-the-modern-v-flag/6ad25033fa0a675c845f251a) ### [Demystifying Regular Expressions: From NFA Backtracking and ReDoS to the Modern /v Flag](https://eliasmiller.hashnode.dev/demystifying-regular-expressions-from-nfa-backtracking-and-redos-to-the-modern-v-flag?utm_source=hashnode&utm_medium=feed) Exploring the mechanics of NFA state machines, catastrophic backtracking, the stateful lastIndex trap, and modern ECMAScript features. 7 min read · [eliasmiller.hashnode.dev](https://eliasmiller.hashnode.dev/demystifying-regular-expressions-from-nfa-backtracking-and-redos-to-the-modern-v-flag?utm_source=hashnode&utm_medium=feed) [1](https://hashnode.com/posts/demystifying-regular-expressions-from-nfa-backtracking-and-redos-to-the-modern-v-flag/6ad25033fa0a675c845f251a) [SpinHire](https://hashnode.com/@spinhire) · [Oct 13](https://hashnode.com/posts/salary-strings-to-numbers/6ace3dec589670cb1652b163) ### [The €300 that isn't a salary: parsing pay ranges out of free text](https://spinhire.hashnode.dev/salary-strings-to-numbers?utm_source=hashnode&utm_medium=feed) Context windows, perk words, period guessing and why we drop a range rather than guess wrong 9 min read · [spinhire.hashnode.dev](https://spinhire.hashnode.dev/salary-strings-to-numbers?utm_source=hashnode&utm_medium=feed) [Kirnu (كرنو)](https://hashnode.com/@kirnu) · [Oct 8](https://hashnode.com/posts/arabic-digits-in-web-forms-why-a-valid-phone-number-gets-rejected-and-how-to-fix-it-in-javascript/6ac7a3467f4eed1b443ab96d) ### [Arabic digits in web forms - why a valid phone number gets rejected, and how to fix it in JavaScript](https://kirnu.hashnode.dev/arabic-digits-in-web-forms-why-a-valid-phone-number-gets-rejected-and-how-to-fix-it-in-javascript?utm_source=hashnode&utm_medium=feed) Why \\d, Number() and \\p{Nd} fail on Arabic-Indic digits, and how to normalize, validate and store phone numbers and amounts in JavaScript. 6 min read · [kirnu.hashnode.dev](https://kirnu.hashnode.dev/arabic-digits-in-web-forms-why-a-valid-phone-number-gets-rejected-and-how-to-fix-it-in-javascript?utm_source=hashnode&utm_medium=feed) [ZyVOP](https://hashnode.com/@zyvop) · [Sep 27](https://hashnode.com/posts/big-o-notation-explained-the-regex-that-took-down-cloudflare-for-27-minutes/6ab8e5f127e2fea745c72b0c) ### [Big-O Notation Explained: The Regex That Took Down Cloudflare for 27 Minutes](https://blog.zyvop.com/big-o-notation-explained-the-regex-that-took-down-cloudflare-for-27-minutes?utm_source=hashnode&utm_medium=feed) Day 1 of the DSA Mastery Series — the concept every post after this one leans on 11 min read · [blog.zyvop.com](https://blog.zyvop.com/big-o-notation-explained-the-regex-that-took-down-cloudflare-for-27-minutes?utm_source=hashnode&utm_medium=feed) [SpinHire](https://hashnode.com/@spinhire) · [Sep 18](https://hashnode.com/posts/normalizing-job-postings-lessons/6aad3d99066cccffbfd6b254) ### [Montana is not Malta: what we learned normalizing thousands of job postings](https://spinhire.hashnode.dev/normalizing-job-postings-lessons?utm_source=hashnode&utm_medium=feed) ATS APIs, a 1-vCPU box, SQLite in WAL mode and a surprising amount of string matching 6 min read · [spinhire.hashnode.dev](https://spinhire.hashnode.dev/normalizing-job-postings-lessons?utm_source=hashnode&utm_medium=feed)