.. _auto_string_regex:

*STRING REGEX*
==============

Applies a regular-expression pattern to an input string and returns the first match. Use this worker whenever a workflow needs to extract or validate a substring from a scalar text value using standard regex syntax.

When to use
-----------

Classification: **process**.

Tagged: ``pattern_matching``, ``regex``, ``scalar``, ``string``, ``text_extraction``, ``transformation``.

Inputs
------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20 20 20

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Response
     - response
     - scalar
     - —
     - ✓
     - The input string (haystack) to search; provide any scalar text value from which the regex pattern should be matched.
   * - Regex
     - regex
     - scalar
     - —
     - ✓
     - The regular-expression pattern (needle) to match against the input string — supplied without surrounding delimiters, as the worker automatically wraps the value in forward slashes (e.g. supply `\d+` not `/\d+/`).

Outputs
-------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20

   * - Label
     - ID
     - Type
     - Description
   * - string_regex_output_1
     - string_regex_output_1
     - scalar
     - The first substring matched by the supplied regular-expression pattern; returns an empty/null scalar if no match is found.

Disciplines
-----------

- data.dataset.transform

Runnable example
----------------

A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: `/api/workflow/example?id=string_regex <https://www.d3view.com/api/workflow/example?id=string_regex>`_

.. raw:: html

   <hr style="margin-top:2em">
   <p style="font-size:11px;color:#888">
   Auto-generated from <code>transformation</code> schema. Worker id: <code>string_regex</code>. Schema hash: <code>075351b8ea19</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>