coinmarketcap volume weighted mcap

import os
import argparse
from typing import NamedTuple
from coinmarketcapapi import CoinMarketCapAPI, CoinMarketCapAPIError

api_key = os.environ["COINMARKETCAP_API_KEY"]

cmc = CoinMarketCapAPI(api_key)


class Dat(NamedTuple):
    symbol: str
    mcap: float
    volume: int
    last: str
    price: float
    change24: float

def main():
    r = cmc.cryptocurrency_listings_latest(sort="market_cap")

    total_vm = 0
    data = r.data

    args = parse_args()

    for ent in iterate(data):
        total_vm += ent.mcap * ent.volume

    date = ent.last[0:10]

    print(date)
    print("RANK\tSYM   \tMCAP\tCHANGE")

    for i, ent in enumerate(iterate(data)):
        rank = i + 1
        pct = ent.mcap * ent.volume/total_vm
        vwcap = ent.mcap * pct
        out = "{rank}\t{symbol}\t{pct:.2%}\t{change:.2%}".format(symbol=ent.symbol, pct=pct, rank=rank, change=ent.change24)
        if rank <= args.top:
            print(out)


def iterate(data):
    for ent in data:
        symbol = ent["symbol"]
        tags = ent["tags"]
        price = ent["quote"]["USD"]["price"]
        if "stablecoin" in tags:
            continue
        mcap = ent["quote"]["USD"]["market_cap"]
        volume = ent["quote"]["USD"]["volume_24h"]
        change24 = ent["quote"]["USD"]["percent_change_24h"] / 100.0
        last = ent["last_updated"]
        dat = Dat(symbol, mcap, volume, last, price, change24)
        yield dat

def parse_args():
    parser = argparse.ArgumentParser(description='Volume weighted market cap')
    parser.add_argument('top', type=int, default=10, help='print the top ranks', nargs="?")
    return parser.parse_args()


if __name__ == "__main__":
    main()