calc_rich_totals.py

#!/usr/bin/env python3
"""Calculate aggregate rich-list wealth totals and growth metrics.

Reports row counts, total current wealth, total last-year wealth, nominal
year-over-year growth, and CPI-adjusted growth. CPI adjustment uses the fixed
`CPI_YOY_PCT` constant (currently 4.6%) to inflation-adjust last year's wealth
before calculating adjusted growth.

Usage:
  python3 calc_rich_totals.py
  python3 calc_rich_totals.py --only-billionaires

Options:
  --only-billionaires  Include only rows where current wealth is at least $1B.
"""

from __future__ import annotations

import argparse
import csv
import re
from pathlib import Path

INPUT_CSV = Path("rich_list_table.csv")
BILLION_DOLLARS = 1_000_000_000.0
CPI_YOY_PCT = 4.6

MONEY_RE = re.compile(r"\$\s*([0-9][0-9,]*(?:\.[0-9]+)?)\s*([bm]?)", re.IGNORECASE)
UNIT_MULTIPLIER = {"": 1.0, "m": 1_000_000.0, "b": 1_000_000_000.0}


def parse_money(value: str) -> float | None:
    match = MONEY_RE.search((value or "").strip())
    if not match:
        return None
    amount = float(match.group(1).replace(",", ""))
    unit = match.group(2).lower()
    return amount * UNIT_MULTIPLIER[unit]


def format_number(value: float) -> str:
    rounded = round(value, 2)
    return f"{rounded:.2f}".rstrip("0").rstrip(".")


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Calculate aggregate wealth totals.")
    parser.add_argument(
        "--only-billionaires",
        action="store_true",
        help="Only include rows where current wealth is at least $1B.",
    )
    return parser.parse_args()


def main() -> None:
    args = parse_args()
    total_rows = 0
    used_rows = 0
    total_wealth = 0.0
    total_wealth_last_year = 0.0

    with INPUT_CSV.open(newline="", encoding="utf-8") as csv_file:
        for row in csv.DictReader(csv_file):
            total_rows += 1
            wealth = parse_money(row.get("wealth", ""))
            wealth_last_year = parse_money(row.get("wealth_last_year", ""))
            if wealth is None or wealth_last_year is None:
                continue
            if args.only_billionaires and wealth < BILLION_DOLLARS:
                continue

            used_rows += 1
            total_wealth += wealth
            total_wealth_last_year += wealth_last_year

    yoy_growth_pct = None
    if total_wealth_last_year:
        yoy_growth_pct = ((total_wealth - total_wealth_last_year) / total_wealth_last_year) * 100

    total_wealth_b = total_wealth / BILLION_DOLLARS
    total_wealth_last_year_b = total_wealth_last_year / BILLION_DOLLARS
    total_growth_b = total_wealth_b - total_wealth_last_year_b
    cpi_multiplier = 1 + (CPI_YOY_PCT / 100)
    total_wealth_last_year_b_adjusted = total_wealth_last_year_b * cpi_multiplier
    total_growth_b_adjusted = total_wealth_b - total_wealth_last_year_b_adjusted

    yoy_growth_pct_adjusted = None
    if total_wealth_last_year_b_adjusted:
        yoy_growth_pct_adjusted = (total_growth_b_adjusted / total_wealth_last_year_b_adjusted) * 100

    print(f"rows {total_rows}")
    print(f"rows_excluded {total_rows - used_rows}")
    print(f"total_wealth_b_dollars {format_number(total_wealth_b)}")
    print(f"total_wealth_last_year_b_dollars {format_number(total_wealth_last_year_b)}")
    print(f"total_wealth_last_year_b_dollars_adjusted {format_number(total_wealth_last_year_b_adjusted)}")
    print(f"total_growth_b_dollars {format_number(total_growth_b)}")
    print(f"total_growth_b_dollars_adjusted {format_number(total_growth_b_adjusted)}")
    print(f"yoy_growth_pct {format_number(yoy_growth_pct) if yoy_growth_pct is not None else 'n/a'}")
    print(
        f"yoy_growth_pct_adjusted {format_number(yoy_growth_pct_adjusted) if yoy_growth_pct_adjusted is not None else 'n/a'}"
    )


if __name__ == "__main__":
    main()

calc_rich_totals.py.output.txt

> calc_rich_totals.py --only-billionaires
rows 200
rows_excluded 32
total_wealth_b_dollars 672.23
total_wealth_last_year_b_dollars 641.5
total_wealth_last_year_b_dollars_adjusted 671.01
total_growth_b_dollars 30.73
total_growth_b_dollars_adjusted 1.22
yoy_growth_pct 4.79
yoy_growth_pct_adjusted 0.18

rich_list_table.csv

rich_list_totals_model.xlsx