Simple CSV parser function and example plotter program compatible with _some_ RIGOL oscilloscopes

example.py

#!/usr/bin/env python3
from oscilloscope import parse_csv_export, ParsedCSV
import argparse
from io import TextIOWrapper
import matplotlib.pyplot as plt


def main():
    parser = argparse.ArgumentParser(description="Example plotter")
    parser.add_argument("infile", type=argparse.FileType('r'))
    file: TextIOWrapper = parser.parse_args().infile
    data = parse_csv_export(file)
    plt.plot(*list(map(list, zip(*data.points))))
    plt.xlabel(f"{data.axis_names[0]} ({data.axis_units[0]})")
    plt.ylabel(f"{data.axis_names[1]} ({data.axis_units[1]})")
    plt.show()


if __name__ == "__main__":
    main()

oscilloscope.py

#!/usr/bin/env python3
from io import TextIOWrapper
from typing import Tuple, List, NamedTuple
import csv


class ParsedCSV(NamedTuple):
    axis_names: Tuple[str, str]
    axis_units: Tuple[str, str]
    points: List[Tuple[float, float]]


def parse_csv_export(file: TextIOWrapper) -> ParsedCSV:
    bad_format = ValueError("File is not a valid oscilloscope export")
    table = csv.reader(file, dialect="unix")
    table_iter = iter(table)
    names = tuple(next(table_iter)[0:-1])
    units = tuple(next(table_iter)[0:-1])
    data = list()
    if len(names) != 2 or len(units) != 2:
        raise bad_format

    for row in table_iter:
        try:
            pair = tuple(map(float, row[0: -1]))
        except ValueError:
            raise bad_format
        if len(pair) != 2:
            raise bad_format
        data.append(pair)

    return ParsedCSV(names, units, data)