rolling-average-ticker-price.py

rolling-average-ticker-price.py

# /// script
# dependencies = [
# "yfinance",
# ]
# ///

import yfinance as yf
from datetime import datetime, date
import argparse
import pandas as pd


def _get_past_trading_date(trading_days_ago: int) -> date:
    """Calculates a date in the past, considering only trading days.

    Parameters
    ----------
    trading_days_ago
        The number of trading days ago.

    Returns
    -------
    date
        The past date.

    """
    today = pd.Timestamp(datetime.today())
    past_date = today - pd.tseries.offsets.BusinessDay(n=trading_days_ago)
    return past_date.date()


def get_average_stock_price(ticker: str, trading_days_ago: int) -> float | None:
    """Calculates the average stock price (closing price) of a given ticker over a specified period.

    Parameters
    ----------
    ticker
        The stock ticker symbol (e.g., 'MSFT').
    trading_days_ago
        The number of days in the past to calculate the average from.

    Returns
    -------
    float | None
        The average closing price, or None if data is unavailable.

    """
    start_date = _get_past_trading_date(trading_days_ago)
    end_date = _get_past_trading_date(0)

    data = yf.download(ticker, start=start_date, end=end_date)

    if data.empty:
        return None

    average_price = data["Close"].mean()
    return average_price


def main() -> None:
    """Main function."""
    parser = argparse.ArgumentParser(
        description="Calculate the average stock price of a given ticker over a specified period."
    )
    parser.add_argument("--ticker", type=str, help="The stock ticker symbol (e.g., MSFT)")
    parser.add_argument("--days", type=int, help="The number of days in the past")
    args = parser.parse_args()

    average_price = get_average_stock_price(args.ticker, args.days)

    if average_price is not None:
        print(
            f"The average closing price of {args.ticker} over the last {args.days} trading days is: "
            f"${float(average_price):.2f}"  # Explicitly cast to float
        )
    else:
        print(f"Could not retrieve data for {args.ticker}")


if __name__ == "__main__":
    main()