Probador de regex

Test regular expressions with match highlighting, capture groups, and replace preview. Gratis, privado y 100% del lado del cliente.

PatrónModoReemplazoGlobal (g)Ignorar mayúsculas (i)Multilínea (m)Punto todo (s)

Entrada

Probar un ejemplo:

Salida

Local only

Historial reciente

Sin historial aún

Uso

Enter the regular expression pattern.
Paste the test text into the input box.
Toggle flags and read matches with capture groups.

Tareas que usan esta herramienta

Analizar SQL consulta ejecución planes

EXPLAIN muestra cómo el base de datos executes un consulta. Aprender a leer planes, identificar cuellos de botella, y optimizar.

Calcular edit distance (Levenshtein)

Editar distance measures el minimum número de insertions, deletions, y substitutions a transformar one cadena en another. Usado en spell checking y fuzzy matching.

Calcular Levenshtein distance

Levenshtein distance measures el minimum edits (insert, eliminar, substitute) a transformar one cadena en another. Usado en spell checking y fuzzy matching.

Calcular TF-IDF for text importance

TF-IDF (Término Frequency-Inverse Documento Frequency) measures palabra importance en un documento relative a un corpus. Usado en search y texto mining.

Depurar regex patrones paso por paso

Depurar regex por testing against sample inputs, visualizing el coincidir, y understanding por qué un patrón matches o fails. Usar flags correctly.

Extraer all URLs from a block of text

Buscar cada URL (http, https, ftp) en unstructured texto y list them para validation, deduplication, o batch processing.

Extraer hashtags from text

Hashtags iniciar con # followed por letters, números, y underscores. Aprender a extraer, validar, y normalizar hashtags de social media texto.

Extraer @mentions from text

Mentions iniciar con @ followed por un username. Aprender a extraer mentions, validar usernames, y link them a usuario profiles.

Buscar y reemplazar texto usando un regular expression

Search para patrones (no solo literal cadenas) en texto y reemplazar matches con un template ese puede referencia capture groups.

Formatear and beautify SQL statements

SQL formatting improves readability y maintainability. Aprender indentation reglas, keyword alignment, y consistent style para complejo queries.

Design base de datos indexes para performance

Indexes speed up reads pero lento down writes. Aprender B-tree, hash, composite, y partial indexes, y cuando a usar cada.

Optimizar regex para performance

Lento regex puede cause ReDoS (Regular Expression Denial de Servicio). Aprender a identificar y fix catastrophic backtracking, usar atomic groups, y anchor patrones.

Optimizar lento SQL queries

Identificar y fix lento SQL queries usando EXPLAIN análisis, index optimization, y consulta rewriting techniques.

Eliminar stop words from text

Detener palabras son común palabras (el, es, at, que) ese añadir little meaning. Removing them improves search y NLP efficiency.

Probar un regular expression antes shipping it

Validar pattern syntax, inspect every match with capture groups, and learn the backtracking pitfalls that turn a regex into an outage.

Tokenize texto para NLP processing

Tokenization splits texto en tokens (palabras, sentences, subwords). Aprender palabra, sentence, y subword tokenization para NLP tareas.

Implement lleno-texto search en SQL

Lleno-texto search indexes palabras en texto para rápido searching. Aprender a usar FULLTEXT indexes, tsvector, y ranking.

Usar regex backreferences

Backreferences \1, \2, ... coincidir el mismo texto como un anterior capturing group. Useful para matching repeated palabras, paired delimiters, y palindromes.

Usar regex carácter clases effectively

Carácter clases [...] coincidir any one carácter de un establecer. Aprender ranges, negation, shorthand clases, y escaping reglas.

Usar regex capturing y non-capturing groups

Groups (...) capture submatches para backreferences y extraction. Non-capturing (?:...) group sin capturing. Named groups (?<name>...) improve readability.

Usar regex lookahead assertions

Lookahead (?=...) y (?!...) assert qué follows (o doesn't follow) el actual position sin consuming caracteres. Zero-ancho assertions.

Usar regex lookbehind assertions

Lookbehind (?<=...) y (?<!...) assert qué precedes el actual position. Supported en moderno engines (ES2018+, Java, .NET, PCRE).

Usar regex quantifiers: *, +, ?, {n,m}

Quantifiers specify cómo muchos times un patrón repeats. Aprender greedy, lazy, y possessive matching a avoid catastrophic backtracking.

Validar SQL syntax before execution

Validar SQL queries for syntax errors before sending to the database. Catch typos, missing keywords, and structural issues early.

Write un robust email validation regex

Email validation regex es notoriously complejo due a RFC 5322. Aprender practical patrones para común usar cases y sus limitations.

Write phone número validation regex

Phone números vary wildly por country. Aprender practical regex patrones para común formats y por qué un phone library es a menudo better.

Write un URL validation regex

URL validation regex debe handle protocol, domain, port, path, consulta, y fragment. Aprender practical patrones y cuando a usar un URL parser instead.

Preguntas frecuentes

What happens with catastrophic backtracking?: Matching runs in a Web Worker with a timeout. If it exceeds the limit, the tool reports a timeout instead of freezing the page. This protects against patterns like (a+)+ on adversarial input.
Which flags are supported?: Global (g), ignore case (i), multiline (m), and dotAll (s) can be toggled independently. The unicode (u) flag is enabled by default for correct handling of surrogate pairs.
How are capture groups shown?: Each match lists its full match text and numbered capture groups. Named groups (?<name>...) are displayed with their names.
Can I preview replacements?: Yes. Enter a replacement string (with $1, $2, $& references) and the tool shows the replaced output alongside the original, with diffs highlighted.
Which regex flavor is used?: The tool uses the JavaScript RegExp engine (ECMAScript). Lookbehind assertions (?<=...) and (?<!...) are supported in modern browsers. POSIX classes and PCRE-specific features are not.
Is my input uploaded anywhere?: No. All matching happens locally in a Web Worker. Your pattern and test text never leave the browser.

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Convert text between upper, lower, title, camel, pascal, snake, kebab, constant, and sentence cases. Gratis, privado y 100% del lado del cliente.

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Count characters, words, lines, sentences, paragraphs, byte size, and estimate reading time. Gratis, privado y 100% del lado del cliente.