csv.py

import logging

import pandas as pd
import pyarrow
import pyarrow.csv

from .registry import register_array_parser


@register_array_parser("csv")
class CSVArrayParser(object):
    def __init__(self, delimiter=","):
        self.delimiter = delimiter

    def read(self, path):
        logging.info(
            "Reading from %s using CSV format with configuration %s"
            % (path, self.__dict__)
        )
        # do not read the first line as header
        read_options = pyarrow.csv.ReadOptions(autogenerate_column_names=True)
        parse_options = pyarrow.csv.ParseOptions(delimiter=self.delimiter)
        arr = pyarrow.csv.read_csv(
            path, read_options=read_options, parse_options=parse_options
        )
        logging.info("Done reading from %s" % path)
        return arr.to_pandas().to_numpy()

    def write(self, path, arr):
        logging.info(
            "Writing to %s using CSV format with configuration %s"
            % (path, self.__dict__)
        )
        write_options = pyarrow.csv.WriteOptions(
            include_header=False, delimiter=self.delimiter
        )
        arr = pyarrow.Table.from_pandas(pd.DataFrame(arr))
        pyarrow.csv.write_csv(arr, path, write_options=write_options)
        logging.info("Done writing to %s" % path)