# This code is supporting material for the book

# Building Machine Learning Systems with Python

# by Willi Richert and Luis Pedro Coelho

# published by PACKT Publishing

#

# It is made available under the MIT License

import scipy as sp

def tfidf(t, d, D):

tf = float(d.count(t)) / sum(d.count(w) for w in set(d))

idf = sp.log(float(len(D)) / (len([doc for doc in D if t in doc])))

return tf * idf

a, abb, abc = ["a"], ["a", "b", "b"], ["a", "b", "c"]

D = [a, abb, abc]

print(tfidf("a", a, D))

print(tfidf("b", abb, D))

print(tfidf("a", abc, D))

print(tfidf("b", abc, D))

print(tfidf("c", abc, D))