"""CSV formatter for PyArrow tables."""
import io
import pyarrow as pa
import pyarrow.csv as csv
def format_csv(arrow_table: pa.Table) -> str:
r"""
Format Arrow table as CSV string.
Uses PyArrow's native CSV writer for memory efficiency and proper escaping.
Args:
arrow_table (pa.Table): PyArrow Table to format
Returns:
str: CSV-formatted string with header row.
Example: "id,name\\n1,Alice\\n2,Bob\\n"
Note:
PyArrow's csv.write_csv() handles escaping automatically:
- Commas in values are quoted
- Quotes in values are escaped
- Newlines in values are preserved within quotes
"""
output = io.BytesIO()
csv.write_csv(arrow_table, output)
return output.getvalue().decode("utf-8")
