import numpy as np
from sklearn.datasets import load_digits
from sklearn.decomposition import PCA
from sklearn.preprocessing import StandardScaler

X, _ = load_digits(return_X_y=True)
active_std = X.std(axis=0)
active_std = active_std[active_std > 0]

print(f"original shape: {X.shape}")
print(
    "raw active-feature std range: "
    f"{active_std.min():.4f} to {active_std.max():.4f}"
)