Python-给定2个句子字符串，计算余弦相似度

一个简单的纯Python实现是：

import re, mathfrom collections import CounterWORD = re.compile(r'w+')def get_cosine(vec1, vec2):     intersection = set(vec1.keys()) & set(vec2.keys())     numerator = sum([vec1[x] * vec2[x] for x in intersection])     sum1 = sum([vec1[x]**2 for x in vec1.keys()])     sum2 = sum([vec2[x]**2 for x in vec2.keys()])     denominator = math.sqrt(sum1) * math.sqrt(sum2)     if not denominator:        return 0.0     else:        return float(numerator) / denominatordef text_to_vector(text):     words = WORD.findall(text)     return Counter(words)text1 = 'This is a foo bar sentence .'text2 = 'This sentence is similar to a foo bar sentence .'vector1 = text_to_vector(text1)vector2 = text_to_vector(text2)cosine = get_cosine(vector1, vector2)print 'Cosine:', cosine

印刷品：

Cosine: 0.861640436855

这里所用的余弦公式描述这里。

这不包括通过

tf-idf

tf-idf

tfidf

你还可以通过使用更复杂的方法从一段文本中提取单词，对其进行词干或词义化等来进一步开发它。