… create a basic exporter

from loguru import logger
from pydantic import BaseModel
from r2x_core.exporter import BaseExporter
from r2x_core.store import DataStore
from r2x_core.system import System
from r2x_core import DataFile

# Define model configuration
class MyModelConfig(BaseModel):
    """Configuration for MyModel exporter."""

    model_year: int
    scenario_name: str
    export_timeseries: bool = True

# Create exporter class
class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def __init__(self, config: MyModelConfig, system: System, data_store: DataStore, **kwargs):
        super().__init__(config, system, data_store, **kwargs)
        self.model_year = config.model_year

    def export(self) -> None:
        """Export system to model format."""
        logger.info(f"Exporting to MyModel format for year {self.model_year}")

        # Export components
        self._export_generators()
        self._export_buses()

        # Export time series if enabled
        if self.config.export_timeseries:
            self.export_time_series()

        logger.info("Export complete")

    def _export_generators(self) -> None:
        """Export generators."""
        pass  # Implementation

    def _export_buses(self) -> None:
        """Export buses."""
        pass  # Implementation

    def export_time_series(self) -> None:
        """Export time series (required abstract method)."""
        # Get only time series files from DataStore
        ts_files = [
            df for df in self.data_store.data_files.values()
            if df.is_timeseries
        ]
        for datafile in ts_files:
            logger.info(f"Exporting time series to {datafile.file_path}")
            # Implementation here

# Use the exporter
config = MyModelConfig(model_year=2030, scenario_name="base")
system = System()  # Already populated with components
data_store = DataStore(
    data_files={
        "generators": DataFile(name="generators", file_path="output/generators.csv"),
    },
    folder="/path/to/output",
)
exporter = MyModelExporter(config, system, data_store)
exporter.export()

… export components to CSV files

from loguru import logger
from r2x_core.exporter import BaseExporter

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def _export_generators(self) -> None:
        """Export generator components to CSV."""
        from my_components import Generator

        # Get DataFile configuration for generators
        gen_file = self.data_store.data_files["generators"]

        # Export only Generator components using filter function
        self.system.export_components_to_csv(
            file_path=gen_file.file_path,
            filter_func=lambda c: isinstance(c, Generator),
        )

        logger.info(f"Exported generators to {gen_file.file_path}")

    def _export_high_voltage_buses(self) -> None:
        """Export only high voltage buses."""
        from my_components import Bus

        bus_file = self.data_store.data_files["hv_buses"]

        # Filter by type AND attribute
        self.system.export_components_to_csv(
            file_path=bus_file.file_path,
            filter_func=lambda c: isinstance(c, Bus) and c.voltage > 100,
            fields=["name", "voltage", "area"],  # Select specific fields
            key_mapping={"voltage": "voltage_kv"}  # Rename columns
        )

        logger.info(f"Exported high voltage buses to {bus_file.file_path}")

    def _export_all_components(self) -> None:
        """Export all system components to a single CSV."""
        all_file = self.data_store.data_files["all_components"]

        # Export everything (no filter)
        self.system.export_components_to_csv(
            file_path=all_file.file_path
        )

        logger.info(f"Exported all components to {all_file.file_path}")

… export time series data

from loguru import logger
from r2x_core import BaseExporter, DataFile
from r2x_core.file_types import TableFile, H5File, ParquetFile
import polars as pl

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def export_time_series(self) -> None:
        """Export time series to files."""
        # Get only time series files from DataStore
        timeseries_files = [
            df for df in self.data_store.data_files.values()
            if df.is_timeseries
        ]

        for datafile in timeseries_files:
            self._export_timeseries_file(datafile)
            logger.info(f"Exported time series to {datafile.file_path}")

    def _export_timeseries_file(self, datafile: DataFile) -> None:
        """Export time series based on file type."""
        # Get time series data from system
        ts_data = self._collect_timeseries_data(datafile.name)

        match datafile.file_type:
            case TableFile():
                ts_data.write_csv(datafile.file_path)
            case H5File():
                self._write_h5(datafile, ts_data)
            case ParquetFile():
                ts_data.write_parquet(datafile.file_path)

    def _collect_timeseries_data(self, name: str) -> pl.DataFrame:
        """Collect time series data from components."""
        # Implementation to gather time series
        return pl.DataFrame()  # Placeholder

    def _write_h5(self, datafile: DataFile, data: pl.DataFrame) -> None:
        """Write data to HDF5."""
        import h5py
        with h5py.File(datafile.file_path, "w") as f:
            for col in data.columns:
                f.create_dataset(col, data=data[col].to_numpy())

… handle multi-year time series export

from loguru import logger
from r2x_core import BaseExporter, DataFile
import h5py
import polars as pl

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def _export_to_h5(self, datafile: DataFile) -> None:
        """Export multi-year time series to HDF5."""
        with h5py.File(datafile.file_path, "w") as f:
            # Get time series from system grouped by year
            for component in self.system.get_components():
                ts_data = self.system.get_time_series(component)

                if ts_data is not None:
                    # Organize by year if multi-year data
                    if isinstance(ts_data, dict):
                        # Multi-year: {2020: array, 2021: array, ...}
                        for year, yearly_data in ts_data.items():
                            group_path = f"/{year}/{component.name}"
                            f.create_dataset(group_path, data=yearly_data)
                    else:
                        # Single year
                        f.create_dataset(f"/{component.name}", data=ts_data)

        logger.info(f"Exported multi-year time series to {datafile.file_path}")

… validate export configuration

from r2x_core.exporter import BaseExporter
from r2x_core.exceptions import ExporterError

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def validate_export(self) -> None:
        """Validate system can be exported."""
        # Check required component types exist
        required_types = ["Generator", "Bus", "Branch"]
        for comp_type in required_types:
            components = self.system.get_components_by_type(comp_type)
            if not components:
                raise ExporterError(f"No {comp_type} components found in system")

        # Validate output directory exists
        output_dir = self.data_store.folder
        if not output_dir.exists():
            raise ExporterError(f"Output directory does not exist: {output_dir}")

… use custom export transformations

from loguru import logger
from r2x_core import BaseExporter, DataFile
import polars as pl

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def _export_generators(self) -> None:
        """Export generators with custom transformations."""
        from my_components import Generator

        # Get components as records (list of dicts) using filter
        gen_records = self.system.components_to_records(
            filter_func=lambda c: isinstance(c, Generator)
        )

        # Convert to DataFrame for transformations
        gen_df = pl.DataFrame(gen_records)

        # Apply model-specific transformations
        transformed_df = gen_df.with_columns([
            # Rename columns
            pl.col("max_active_power").alias("PMax_MW"),
            pl.col("min_active_power").alias("PMin_MW"),
            # Add calculated fields
            (pl.col("max_active_power") * 0.95).alias("AvailableCapacity_MW"),
        ]).select([
            # Select and reorder columns for target model
            "name",
            "bus",
            "PMax_MW",
            "PMin_MW",
            "AvailableCapacity_MW",
        ])

        # Write to configured file
        gen_file = self.data_store.data_files["generators"]
        transformed_df.write_csv(gen_file.file_path)

        logger.info(f"Exported {len(transformed_df)} generators to {gen_file.file_path}")

… export with progress logging

from loguru import logger
from r2x_core import BaseExporter

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def export(self) -> None:
        """Export with progress logging."""
        logger.info("Starting export process")

        # Export components by type
        component_types = {
            "buses": lambda c: c.__class__.__name__ == "Bus",
            "generators": lambda c: c.__class__.__name__ == "Generator",
            "branches": lambda c: c.__class__.__name__ == "Branch",
            "loads": lambda c: c.__class__.__name__ == "Load",
        }

        for name, filter_func in component_types.items():
            # Count matching components
            count = len(self.system.components_to_records(filter_func=filter_func))
            logger.info(f"Exporting {count} {name} components")
            self._export_component_type(name, filter_func)

        # Export time series
        if self.config.export_timeseries:
            timeseries_files = [
                df for df in self.data_store.data_files.values()
                if df.is_timeseries
            ]
            logger.info(f"Exporting {len(timeseries_files)} time series files")
            for datafile in timeseries_files:
                logger.info(f"  - {datafile.name}")
                self._export_timeseries_file(datafile)

        logger.info("Export complete")

    def export_time_series(self) -> None:
        """Export time series (required abstract method)."""
        # Implementation moved to export() method for this example
        pass

    def _export_component_type(self, file_key: str, filter_func) -> None:
        """Export specific component type."""
        if file_key in self.data_store.data_files:
            datafile = self.data_store.data_files[file_key]
            self.system.export_components_to_csv(
                file_path=datafile.file_path,
                filter_func=filter_func,
            )

    def _export_timeseries_file(self, datafile) -> None:
        """Export time series file."""
        pass  # Implementation

… handle optional time series files

from loguru import logger
from r2x_core import BaseExporter, DataFile

class MyModelExporter(BaseExporter):
    """Exporter for MyModel format."""

    def export_time_series(self) -> None:
        """Export time series, handling optional files."""
        timeseries_files = [
            df for df in self.data_store.data_files.values()
            if df.is_timeseries
        ]

        for datafile in timeseries_files:
            # Check if this is an optional file
            if datafile.is_optional:
                # Check if data exists before exporting
                if self._has_timeseries_data(datafile.name):
                    self._export_timeseries_file(datafile)
                else:
                    logger.info(f"Skipping optional file {datafile.name} (no data)")
            else:
                # Required file - must export
                self._export_timeseries_file(datafile)

    def _has_timeseries_data(self, name: str) -> bool:
        """Check if time series data exists for this file."""
        # Check if any components have time series matching this name
        for component in self.system.get_components():
            ts_data = self.system.get_time_series(component)
            if ts_data is not None and name in str(ts_data):
                return True
        return False

    def _export_timeseries_file(self, datafile: DataFile) -> None:
        """Export time series file."""
        pass  # Implementation