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2026-07-13 13:26:28 +08:00

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2.7 KiB
Python

"""ETF universe loader."""
import polars as pl
from data.exceptions import DataNotFoundError
from utils import ML4T_DATA_PATH
from utils.data_quality import apply_max_symbols
def list_etfs() -> list[str]:
"""List ETF symbols available in the local data store.
Returns:
Sorted list of ETF tickers (e.g., ``["ACWI", "AGG", ..., "XLK"]``).
Raises:
DataNotFoundError: If ``etfs/etf_universe.parquet`` is missing.
Example:
>>> list_etfs()[:3]
['ACWI', 'ACWX', 'AGG']
"""
path = ML4T_DATA_PATH / "etfs" / "market" / "etf_universe.parquet"
if not path.exists():
raise DataNotFoundError(
dataset_name="ETF Universe",
path=path,
download_script="data/etfs/market/download.py",
readme="data/etfs/README.md",
)
return pl.scan_parquet(path).select("symbol").unique().collect().to_series().sort().to_list()
def load_etfs(
symbols: list[str] | None = None,
start_date: str | None = None,
end_date: str | None = None,
max_symbols: int = 0,
) -> pl.DataFrame:
"""Load ETF universe for momentum case study.
Args:
symbols: Optional list of symbols to filter (e.g., ["SPY", "QQQ"])
start_date: Optional start date (YYYY-MM-DD format)
end_date: Optional end date (YYYY-MM-DD format)
max_symbols: Limit to N random symbols (0 = all). Seed-deterministic.
Returns:
DataFrame with columns: timestamp, symbol, open, high, low, close, volume
"""
path = ML4T_DATA_PATH / "etfs" / "market" / "etf_universe.parquet"
if not path.exists():
raise DataNotFoundError(
dataset_name="ETF Universe",
path=path,
download_script="data/etfs/market/download.py",
readme="data/etfs/README.md",
)
lf = pl.scan_parquet(path)
ts_type = lf.collect_schema()["timestamp"]
# Apply filters lazily (parquet pushdown / row-group pruning)
if symbols:
lf = lf.filter(pl.col("symbol").is_in(symbols))
if start_date:
lit = (
pl.lit(start_date).str.to_date()
if ts_type == pl.Date
else pl.lit(start_date).str.to_datetime()
)
lf = lf.filter(pl.col("timestamp") >= lit)
if end_date:
lit = (
pl.lit(end_date).str.to_date()
if ts_type == pl.Date
else pl.lit(end_date).str.to_datetime()
)
lf = lf.filter(pl.col("timestamp") <= lit)
# Normalize daily data to Date type (post-filter so pushdown works on raw type)
if ts_type != pl.Date:
lf = lf.with_columns(pl.col("timestamp").cast(pl.Date))
return apply_max_symbols(lf.collect(), max_symbols)