Export component records and filter keyword arguments

The helpers in r2x_core.utils work with ordinary systems, paths and callables. This tutorial creates its own components and temporary output; it needs no model dataset. Use the exact public module imports below on current main.

Select and rename record fields

A model dump normally includes a UUID. Selecting named fields makes the result deterministic and limits an export to the intended contract.

>>> from infrasys import Component
>>> from r2x_core import System
>>> from r2x_core.utils import components_to_records
>>> class Generator(Component):
...     capacity_mw: float
>>> system = System(name="demo")
>>> system.add_component(Generator(name="Alpha", capacity_mw=100.0))
>>> records = components_to_records(system, fields=["name", "capacity_mw"], key_mapping={"capacity_mw": "capacity"})
>>> # Expected: selected fields are retained and the output key is renamed.
>>> records
[{'name': 'Alpha', 'capacity': 100.0}]
>>> selected = components_to_records(system, fields=["name"], filter_func=lambda component: component.capacity_mw > 200)
>>> selected
[]

Write and check a CSV

This independent example uses generic named components. The temporary directory is removed after the check, so no persistent user files are modified.

>>> import csv
>>> from pathlib import Path
>>> from tempfile import TemporaryDirectory
>>> from infrasys import Component
>>> from r2x_core import System
>>> from r2x_core.utils import export_components_to_csv
>>> system = System(name="csv-demo")
>>> system.add_component(Component(name="Alpha"))
>>> with TemporaryDirectory() as directory:
...     output = Path(directory) / "components.csv"
...     export_components_to_csv(system, file_path=output, fields=["name"])
...     with output.open(encoding="utf-8", newline="") as stream:
...         rows = list(csv.DictReader(stream))
>>> # Expected: the file contains the exported component name.
>>> rows
[{'name': 'Alpha'}]

Filter arguments for a known callable

filter_kwargs_for filters keys by a callable’s accepted parameters; it does not validate values or implement a model transformation.

>>> from r2x_core.utils import filter_kwargs_for
>>> def scale(value: float, *, factor: float = 2.0) -> float:
...     return value * factor
>>> options = filter_kwargs_for(scale, kwargs={"factor": 3.0, "unused": "ignored"})
>>> # Expected: unknown keys are removed before calling the function.
>>> options
{'factor': 3.0}
>>> scale(4.0, **options)
12.0

See Utilities for exact signatures and Export a system for an artifact that preserves system metadata and companion storage. A CSV record export is a different boundary.

For registered getter functions, use the getter API contract and resolve_getter contract.