# Transform each row with code

Control / script

A variant of [Run a script](https://meridian.online/operations/run-a-script).

Run a user function or snippet on every row, value or column to compute or change fields.

Page: <https://meridian.online/operations/run-a-script/transform-rows-with-code>

## Status

Not built yet.

arcform does not do this yet; it would live in how a Protocol runs. [Its place on the roadmap](https://meridian.online/roadmap#run-a-script)

## What other tools call it

Meridian's classification; an independent blind rating agreed on 95.7% of 324 rows (variant, version 3).

- Duckle: [`JavaScript UDF`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/website/docs/components.html) (read 2026-09-25)
- Duckle: [`Python UDF`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/website/docs/components.html) (read 2026-09-25)
- Duckle: [`WebAssembly UDF`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/website/docs/components.html) (read 2026-09-25)
- AWS Glue: [`Map`](https://docs.aws.amazon.com/glue/latest/dg/aws-glue-api-crawler-pyspark-transforms-map.html) (read 2026-09-27)
- Apache Hop: [`JavaScript`](https://hop.apache.org/manual/latest/pipeline/transforms/javascript.html) (read 2026-09-27)
- Apache Hop: [`Script`](https://hop.apache.org/manual/latest/pipeline/transforms/script.html) (read 2026-09-27)
- KNIME Analytics Platform: [`Java Snippet`](https://api.hub.knime.com/nodes/*QNB4FsAPnEAgOMVh?details=full) (read 2026-09-27)
- KNIME Analytics Platform: [`Java Snippet (simple)`](https://api.hub.knime.com/nodes/*NEtdObxjUs6xOdsw?details=full) (read 2026-09-27)
- Apache NiFi: [`ScriptedTransformRecord`](https://nifi.apache.org/components/org.apache.nifi.processors.script.ScriptedTransformRecord/) (read 2026-09-27)
- OpenRefine: [`Clojure`](https://openrefine.org/docs/manual/jythonclojure#clojure) (read 2026-09-27)
- OpenRefine: [`Jython`](https://openrefine.org/docs/manual/jythonclojure#jython) (read 2026-09-27)
- Pentaho Data Integration: [`Modified Java Script Value`](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview) (read 2026-09-27)
- Pentaho Data Integration: [`Script`](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview) (read 2026-09-27)
- Polars: [`DataFrame.map_columns`](https://docs.pola.rs/api/python/stable/reference/dataframe/miscellaneous.html) (read 2026-09-27)
- Polars: [`DataFrame.map_rows`](https://docs.pola.rs/api/python/stable/reference/dataframe/miscellaneous.html) (read 2026-09-27)
- Polars: [`Expr.map_batches`](https://docs.pola.rs/api/python/stable/reference/expressions/functions.html) (read 2026-09-27)
- Polars: [`Expr.map_elements`](https://docs.pola.rs/api/python/stable/reference/expressions/functions.html) (read 2026-09-27)
- Polars: [`map_batches`](https://docs.pola.rs/api/python/stable/reference/expressions/functions.html) (read 2026-09-27)
- Apache SeaTunnel: [`DynamicCompile`](https://seatunnel.apache.org/docs/2.3.13/transforms/dynamic-compile) (read 2026-09-27)
- Apache SeaTunnel: [`Python`](https://seatunnel.apache.org/docs/transforms/python) (read 2026-09-27)
- Talend: [`tDotNETRow`](https://help.qlik.com/talend/en-US/components/8.0/dotnet/dotnet-component) (read 2026-09-27)
- Talend: [`tJavaRow`](https://help.qlik.com/talend/en-US/components/8.0/java-custom-code/java-custom-code-component) (read 2026-09-27)
- Trifacta: [`Invoke external function`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27)
- VisiData: [`addcol-shell`](https://github.com/saulpw/visidata/blob/7609212ec2febafa9caba7183cbebfaf49627909/visidata/shell.py#L282) (read 2026-09-23)