Convert Betterment Cost Basis report into a format importable by Yahoo Finance Portfolios.

convert.py

#!/usr/bin/env python

import sys
import argparse
import csv
import operator
import logging
import datetime


def get_trade_date(record):
    purchase_date = record["PurchaseDate"]
    purchase_date = datetime.datetime.strptime(purchase_date, "%m/%d/%Y").date()
    return purchase_date.strftime("%Y%m%d")


def get_purchase_price(record):
    cost_basis = float(record["CostBasis"])
    shares = float(record["Shares"])
    price = cost_basis / shares
    return f"{price:.2f}"


FIELDS = (
    (
        "Symbol",
        operator.itemgetter("Symbol"),
    ),
    (
        "Trade Date",
        get_trade_date,
    ),
    (
        "Purchase Price",
        get_purchase_price,
    ),
    (
        "Quantity",
        operator.itemgetter("Shares"),
    ),
    (
        "Comment",
        lambda _: "Imported from Betterment.",
    ),
)


def map_record(record):
    return {key: value(record) for (key, value) in FIELDS}


def read_input(path):
    if path == "-":
        fp = sys.stdin
        if fp.isatty():
            logging.warning("reading from terminal")
    else:
        fp = open(path, "r")

    reader = csv.DictReader(fp)
    with fp:
        yield from reader


def write_output(path, data):
    if path == "-":
        fp = sys.stdout
    else:
        fp = open(path, "w")

    keys = list(map(operator.itemgetter(0), FIELDS))

    writer = csv.DictWriter(fp, keys)
    with fp:
        writer.writeheader()
        writer.writerows(data)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("input")
    parser.add_argument("output")
    args = parser.parse_args()

    data = read_input(args.input)
    data = map(map_record, data)
    data = sorted(
        data,
        key=lambda record: (
            record["Trade Date"],
            record["Symbol"],
            record["Quantity"],
        ),
    )
    write_output(args.output, data)


if __name__ == "__main__":
    main()