我试图关注 https://pypi.org/project/fancyimpute/
# print mean squared error for the four imputation methods above
ii_mse = ((X_filled_ii[missing_mask] - X[missing_mask]) ** 2).mean()
print("Iterative Imputer norm minimization MSE: %f" % ii_mse)
nnm_mse = ((X_filled_nnm[missing_mask] - X[missing_mask]) ** 2).mean()
print("Nuclear norm minimization MSE: %f" % nnm_mse)
softImpute_mse = ((X_filled_softimpute[missing_mask] - X[missing_mask]) ** 2).mean()
print("SoftImpute MSE: %f" % softImpute_mse)
knn_mse = ((X_filled_knn[missing_mask] - X[missing_mask]) ** 2).mean()
print("knnImpute MSE: %f" % knn_mse)
什么是missing_mask,如何从缺少值的数据框中获取它?