learning/prompts/code-generation/08_io_csv.md

Prompt:
Write the Python code to read data from CSV files using Apache Beam.

Response:
Your Apache Beam pipeline can read data from [CSV files](https://en.wikipedia.org/wiki/Comma-separated_values) using the [TextIO connector](https://beam.apache.org/releases/pydoc/current/apache_beam.io.textio.html).

```python
import logging
import apache_beam as beam

from apache_beam import Map
from apache_beam.io.textio import ReadFromCsv
from apache_beam.options.pipeline_options import PipelineOptions


class CsvOptions(PipelineOptions):
    @classmethod
    def _add_argparse_args(cls, parser):
        parser.add_argument(
            '--file_path',
            help='Csv file path'
        )


def run():
    """
    This pipeline shows how to read from Csv file.
    """

    options = CsvOptions()

    with beam.Pipeline(options=options) as p:

        output = (p | "Read from Csv file" >> ReadFromCsv(
                        path=options.file_path
                    )
                    | "Log Data" >> Map(logging.info))


if __name__ == "__main__":
    logging.getLogger().setLevel(logging.INFO)
    run()
```

The `CsvOptions` class is a custom class that extends the `PipelineOptions` object. This code uses [pipeline options](https://beam.apache.org/documentation/patterns/pipeline-options/) to parse command-line arguments.

The [`ReadFromCsv` transform](https://beam.apache.org/releases/pydoc/current/apache_beam.io.textio.html#apache_beam.io.textio.ReadFromCsv) is a built-in Apache Beam transform that reads data from a CSV file.