import vectorize

import numpy as np

def replace(a, s, v):
    def f(x):
        if x in s:
            return v
        else:
            return x
    return np.vectorize(f, otypes=[object])(a)

def impute(features):
    features = replace(features, set([vectorize.MISSING]), -1)
    # Dummy imputation.
    features = replace(features, set([vectorize.UNKNOWN]), -1)
    return np.array(features, float)