import math
from math import isnan
import pandas as pd
#結巴分詞，切開之後，有分隔符
def jieba_function(sent):
    import jieba
    sent1 = jieba.cut(sent)
    s = []
    for each in sent1:
        s.append(each)
    return ' '.join(str(i) for i in s)
def count_cos_similarity(vec_1, vec_2):
    if len(vec_1) != len(vec_2):
        return 0

    s = sum(vec_1[i] * vec_2[i] for i in range(len(vec_2)))
    den1 = math.sqrt(sum([pow(number, 2) for number in vec_1]))
    den2 = math.sqrt(sum([pow(number, 2) for number in vec_2]))
    return s / (den1 * den2)
#計算文字向量，傳入文字,接受的是字串
def tf(sent1, sent2):
    from sklearn.feature_extraction.text import CountVectorizer

    sent1 = jieba_function(sent1)
    sent2 = jieba_function(sent2)

    count_vec = CountVectorizer()

    sentences = [sent1, sent2]
    print('sentences',sentences)
    print('vector',count_vec.fit_transform(sentences).toarray())## 輸出特徵向量化後的表示
    print('cut_word',count_vec.get_feature_names())#輸出的是切分的詞， 輸出向量各個維度的特徵含義

    #轉換成維度相同的
    vec_1 = count_vec.fit_transform(sentences).toarray()[0]
    vec_2 = count_vec.fit_transform(sentences).toarray()[1]
    similarity=count_cos_similarity(vec_1, vec_2)
    if isnan(similarity):
        similarity=0.0

    print('count_cos_similarity',similarity)
def tfidf(sent1, sent2):
    from sklearn.feature_extraction.text import TfidfVectorizer

    sent1 = jieba_function(sent1)
    sent2 = jieba_function(sent2)

    tfidf_vec = TfidfVectorizer()

    sentences = [sent1, sent2]
    vec_1 = tfidf_vec.fit_transform(sentences).toarray()[0]
    vec_2 = tfidf_vec.fit_transform(sentences).toarray()[1]
    similarity=count_cos_similarity(vec_1, vec_2)
    if isnan(similarity):
        similarity=0.0
    return similarity


if __name__=='__main__':

    sent1 = '我喜歡看電視也喜歡看電影，'
    sent2 = '我不喜歡看電視也不喜歡看電影'
    print('<<<<tf<<<<<<<')
    tf(sent1, sent2)
    print('<<<<tfidf<<<<<<<')
    tfidf(sent1, sent2)