Python:比较不同维度的两个不同tfidf矩阵中的项目

时间:2017-10-16 09:08:43

标签: python scikit-learn tf-idf cosine-similarity

我想在包含许多行的文件上使用TfidfVectorizer(),每个行都包含一个短语。然后,我想要一个带有一小部分短语的测试文件,执行TfidfVectorizer()然后获取原始和测试文件之间的余弦相似性,以便对于测试文件中的给定短语,我检索前N个匹配原始文件。这是我的尝试:

corpus = tuple(open("original.txt").read().split('\n'))
test = tuple(open("test.txt").read().split('\n'))


from sklearn.feature_extraction.text import TfidfVectorizer

tf = TfidfVectorizer(analyzer='word', ngram_range=(1,3), min_df = 0, stop_words = 'english')
tfidf_matrix =  tf.fit_transform(corpus)
tfidf_matrix2 =  tf.fit_transform(test)

from sklearn.metrics.pairwise import linear_kernel 


def new_find_similar(tfidf_matrix2, index, tfidf_matrix, top_n = 5):
    cosine_similarities = linear_kernel(tfidf_matrix2[index:index+1], tfidf_matrix).flatten()
    related_docs_indices = [i for i in cosine_similarities.argsort()[::-1] if i != index]
    return [(index, cosine_similarities[index]) for index in related_docs_indices][0:top_n]


for index, score in find_similar(tfidf_matrix, 1234567):
       print score, corpus[index]

但是我得到了:

for index, score in new_find_similar(tfidf_matrix2, 1000, tfidf_matrix):
       print score, test[index]
Traceback (most recent call last):

  File "<ipython-input-53-2bf1cd465991>", line 1, in <module>
    for index, score in new_find_similar(tfidf_matrix2, 1000, tfidf_matrix):

  File "<ipython-input-51-da874b8d3076>", line 2, in new_find_similar
    cosine_similarities = linear_kernel(tfidf_matrix2[index:index+1], tfidf_matrix).flatten()

  File "C:\Users\arron\AppData\Local\Continuum\Anaconda2\lib\site-packages\sklearn\metrics\pairwise.py", line 734, in linear_kernel
    X, Y = check_pairwise_arrays(X, Y)

  File "C:\Users\arron\AppData\Local\Continuum\Anaconda2\lib\site-packages\sklearn\metrics\pairwise.py", line 122, in check_pairwise_arrays
    X.shape[1], Y.shape[1]))

ValueError: Incompatible dimension for X and Y matrices: X.shape[1] == 66662 while Y.shape[1] == 3332088

我不介意将两个文件合并然后进行转换,但我想确保我不会将测试文件中的任何短语与测试文件中的其他短语进行比较。

任何指针?

1 个答案:

答案 0 :(得分:2)

使用语料库中的数据拟合TfidfVectorizer,然后使用已安装的矢量化器转换测试数据(即,不要两次调用fit_transform):

tfidf_matrix =  tf.fit_transform(corpus)
tfidf_matrix2 =  tf.transform(test)