#!/usr/bin/env python3

import pyarrow as pa
import pyarrow.csv as pc
import pyarrow.parquet as pq
import pandas as pd
import sys

df = None

for file in sys.argv[1:]:

    part = pq.read_table(file).to_pandas()

    if df is None:
        df = part
    else:
        df = pd.concat([df, part], ignore_index=True)

if df is not None:

    table = pa.Table.from_pandas(df)
    pc.write_csv(table, sys.stdout.buffer)