.. _auto_dataset_dataset_to_columns:

*USE DATASET VALUES TO ADD NEW COLUMNS*
=======================================

Expands a dataset column whose cells contain nested datasets by unpacking those nested datasets into new top-level columns on the parent dataset. Use this worker when a column stores embedded dataset objects and you want to flatten them into individual columns, optionally filtering to a subset of sub-columns and controlling the column naming with a prefix.

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

Classification: **process**.

Tagged: ``columns``, ``dataset``, ``expand``, ``flatten``, ``nested-dataset``, ``prefix``, ``transform``, ``unpivot``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Dataset
     - dataset_1
     - dataset
     - —
     - 
     - The parent dataset containing a column whose cells hold nested dataset objects to be expanded into new columns.
   * - Dataset Column Name
     - column_name
     - scalar
     - —
     - 
     - Name of the column in the parent dataset whose cells contain nested datasets; select from the dropdown populated by dataset_1.
   * - Limit To These Columns In The Dataset
     - sub_columns
     - text
     - —
     - 
     - Comma-separated list of column names within the nested dataset to extract; leave blank to expand all available columns.
   * - Prefix
     - prefix
     - text
     - rc_
     - 
     - String prefix prepended to each newly added column name (default: "rc_"); change to avoid name collisions with existing columns.
   * - Drop Dataset Column
     - drop_columns
     - text
     - yes
     - 
     - Whether to remove the original nested-dataset column after expansion; set to "yes" (default) to drop it, or "no" to retain it.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - dataset_add_curves_to_column_output_1
     - dataset_add_curves_to_column_output_1
     - dataset
     - The parent dataset augmented with one new column per extracted sub-column (prefixed as configured), with the original nested-dataset column dropped or retained according to the drop_columns setting.

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=dataset_dataset_to_columns <https://www.d3view.com/api/workflow/example?id=dataset_dataset_to_columns>`_

.. raw:: html

   <hr style="margin-top:2em">
   <p style="font-size:11px;color:#888">
   Auto-generated from <code>transformation</code> schema. Worker id: <code>dataset_dataset_to_columns</code>. Schema hash: <code>aff738bb1d71</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>