Nikolay Petrov nikbpetrov

nikbpetrov / pd-null-as-nan.py

Created March 20, 2026 07:05

pd reads null as NaN

	import pandas as pd

	jsonl = '{"id": "q1", "date": "2025-01-01", "value": 10}\n{"id": "q1", "date": "2025-01-05", "value": null}'
	dfr = pd.read_json(jsonl, lines=True, dtype={"id": str, "date": str}, convert_dates=False)
	dfr["date"] = pd.to_datetime(dfr["date"])

	print(f"Jan 5 value: {dfr.iloc[1]['value']!r} (type: {type(dfr.iloc[1]['value']).__name__})")
	# Jan 5 value: np.float64(nan) (type: float64)