import numpy as np

readings = np.array([18.5, np.nan, np.inf, -np.inf, 21.0])

cleaned = np.nan_to_num(
    readings,
    nan=0.0,
    posinf=100.0,
    neginf=-100.0,
)

print("original:", readings)
print("cleaned:", cleaned)
print("input unchanged:", np.isnan(readings[1]) and np.isposinf(readings[2]))
print("non-finite before:", np.count_nonzero(~np.isfinite(readings)))
print("non-finite after:", np.count_nonzero(~np.isfinite(cleaned)))