Pythonでコサイン類似性(Cosine Similarity)計算のまとめ

scikit-learn

from sklearn.metrics.pairwise import cosine_similarity 
import numpy as np 

a = [2, 15, 3, 25] 
b = [5, 25, 8, 28] 

array_1 = np.array([a]) 
array_2 = np.array([b]) 
cos_sim = cosine_similarity(array_1 , array_2) 
print(cos_sim) 
# 結果: 
# [[0.9753719]] 

NumPy

from numpy import dot 
from numpy.linalg import norm 

a = [2, 15, 3, 25] 
b = [5, 25, 8, 28] 

cos_sim = dot(a, b) / (norm(a) * norm(b)) 
print(cos_sim) 
# 結果: 
# 0.9753719044721808