Regular Expressions 101

Community Patterns

1

JSON Parser

Created·2026-07-25 18:00
Flavor·.NET 7.0 (C#)
Description This regular expression is designed to tokenize JSON-like content embedded in INI files. It is not a full JSON validator; instead, it provides a lightweight lexical scanner that identifies structural tokens (objects, arrays, strings, numbers, booleans, null) and ignores comments and whitespace. The token stream is then processed by a hand‑written recursive‑descent parser (with depth‑limit protection) to build a .NET object graph (Dictionary, object], or primitives). Regex Pattern (?//.|/\.?\/)| (?""(?:\\.)"")(?=(?:\s|//.|/\.?\/):)| (?(?true)|(?false)|(?null)|""(?(?:\\.))""|(?-?(?:0|[1-9)(?:\.0-9]+)?(?:[eE?[0-9]+)?))| (?:)| (?\[)| (?,)| (?\])| (?{)| (?})| (?+)| (?[\r\n]+)| (?.+) Named Capture Groups | Group Name | Matches | |------------------|-------------------------------------------------------------------------| | Comment | Single‑line //… or multi‑line /…/ comments (skipped). | | key | A JSON property key (double‑quoted string) followed by a colon (lookahead). | | value | A JSON value – one of: true, false, null, a double‑quoted string, or a number (integer, float, or scientific). | | bool | Sub‑group inside value for true/false (for direct parsing). | | null | Sub‑group for null. | | string | Sub‑group for the content inside double‑quotes (without the quotes). | | number | Sub‑group for numeric literals. | | value_sep | A colon : separating key and value. | | array_open | Left bracket [. | | array_sep | Comma , between array elements. | | array_close | Right bracket ]. | | object_open | Left brace {. | | object_close | Right brace }. | | whitespace | Horizontal whitespace (spaces, tabs) – not newlines. | | newline | Line‑break characters (CR, LF, CRLF). | | undefined | Any other character (should not occur in valid JSON; used as fallback). | Important Notes No recursion – the regex only tokenises; the parser handles nesting and depth limits. Escaped characters inside strings (\n, \t, \", etc.) are not unescaped by the regex – the parser calls UnEscape() when _allowEscapeChars is true. Whitespace and newlines are ignored by the parser (skipped during token iteration). The undefined group uses .+ (not .*) to avoid matching empty positions – this prevents false positives when the scanner reaches the end of the string. Purpose This regex is a solid foundation for building a custom JSON lexer, parser, or tokeniser for .NET projects. Its clear separation of structural elements, comments, and whitespace makes it easy to implement lightweight, hand‑crafted parsers that do not rely on heavy external libraries. It is particularly well‑suited for small to medium‑sized files, configuration blocks, or embedded data fragments, where performance and memory footprint matter. You can adapt the token stream to your own data model, add validation, or transform the JSON on the fly – all while keeping full control over the parsing logic.
Submitted by Pavel Bashkardin
1

ตรวจสอบพยัญชนะต้นตัวสะกดสระและวรรณยุกต์ไทย

Created·2026-01-22 01:36
Updated·2026-01-23 12:42
Flavor·JavaScript
ตรวจสอบพยัญชนะต้น (ต้องมี) ตรวจตัวสะกดสำหรับสระที่ต้องมี ตรวจสอบการวางสระและวรรณยุกต์ไทย หมายเหตุ การตรวจสอบตัวสะกดในภาษาไทยตรวจสอบได้ยากเพราะภาษาไทยเป็นภาษาที่เขียนติด ๆ กันไม่มีการแบ่งคำอย่างชัดเจนทำให้การอ่านภาษาไทยผู้อ่านต้องใช้ความหมายของคำในการตัดสินการอ่านแบ่งคำตามความเหมาะสมเช่นคำว่า "ตากลม" อาจอ่านเป็น "ตาก-ลม" ก็ได้ หรืออ่านเป็น "ตา-กลม"ก็ได้ ดังนั้นการเขียน Regex เพื่อทำการตรวจสอบอาจช่วยได้ระดับหนึ่ง อ่าจมีผิดบ้างถูกบ้าง แต่ก็ถือว่าเป็นเครื่องมือที่ใช้ช่วยเหลือในการตรวจสอบเพิ่มเติมได้ 80% ของความเป็นไปใด้ก็แล้วกันนะครับ หวังว่าการเขียนเพิ่มเติมส่วนนี้ จะมีประโยชน์บ้างไม่มากก็น้อย
Submitted by อธิปัตย์ ล้อวงศ์งาม

Community Library Entry

83

Regular Expression
Created·2014-06-26 09:59
Updated·2023-07-20 15:08
Flavor·Python

r"
^ # get the title of this movie or series (?P<title> [-\w'\"]+ # match separator to later replace into correct title (?P<separator> [ .] ) # note this *must* be lazy for the engine to work ltr not rtl (?: [-\w'\"]+\2 )*? ) # start of movie vs serie check (?: # if this is an episode, lets match the season # number one way or another. if not, the year # of the movie (?: # series. can be a lot prettier if we used perl regex... # make sure this is not just a number in the title followed by our separator. # like, iron man 3 2013 or my.fictional.24.series (?! \d+ \2 ) # now try to match the season number (?: s (?: eason \2? )? )? (?P<season> \d\d? ) # needed to validate the last token is a dot, or whatever. (?: e\d\d? (?:-e?\d\d?)? | x\d\d? )? | # this is likely a movie, match the year (?P<year> [(\]]?\d{4}[)\]]? ) ) # make sure this ends with the separator, otherwise we # might be in the middle of something like "1080p" (?=\2) | # if we get here, this is likely still a movie. # match until one of the keywords (?= BOXSET | XVID | DIVX | LIMITED | UNRATED | PROPER | DTS | AC3 | AAC | BLU[ -]?RAY | HD(?:TV|DVD) | (?:DVD|B[DR]|WEB)RIP | \d+p | [hx]\.?264 ) )
"
gimx
Open regex in editor

Description

A neat regex for finding out whether a given torrent name is a series or a movie.

Returns the full name of the series with the separator needed to make it pretty (ie, replace it with space or what you want). Also returns the season number or the year for the movie/series, depending on what was previously matched.

Submitted by Firas Dib