Question

我是Python的新手。我正在尝试编写一个执行以下操作的函数，并在代码的未来部分重用该函数：（函数的作用）：

在两个列表
将值添加到列表中并计算平均值
将平均值附加到列表
返回资产清单

然后，我想基于上述函数返回的列表进行计算。但是，该函数（即knearest_similarity（tfidf_datamatrix））不返回任何内容。第二个函数（即threshold_function（））中的打印命令不显示任何内容。有人可以看看代码并告诉我我做错了什么。

def knearest_similarity(tfidf_datamatrix):
    k_nearest_cosineMean = []
    for datavector in tfidf_datamatrix:
        cosineValueSet = []
        for trainingvector in tfidf_vectorizer_trainingset:
            cosineValue = cx(datavector, trainingvector)
            cosineValueSet.append(cosineValue)
        similarityMean_of_k_nearest_neighbours = np.mean(heapq.nlargest(k_nearest_neighbours, cosineValueSet))    #the cosine similarity score of top k nearest neighbours
        k_nearest_cosineMean.append(similarityMean_of_k_nearest_neighbours)        
    print k_nearest_cosineMean
    return k_nearest_cosineMean


def threshold_function():  
    mean_cosineScore_mean = np.mean(knearest_similarity(tfidf_matrix_testset))
    std_cosineScore_mean = np.std(knearest_similarity(tfidf_matrix_testset))
    threshold = mean_cosineScore_mean - (3*std_cosineScore_mean)
    print "The Mean of the mean of cosine similarity score for a normal Behaviour:", mean_cosineScore_mean #The mean will be used for finding the threshold
    print "The standard deviation of the mean of cosine similarity score:", std_cosineScore_mean  #The standstart deviation is also used to find threshold
    print "The threshold for normal behaviour should be (Mean - 3*standard deviation):", threshold
    return threshold

修改

我尝试为要使用的函数定义两个全局变量（即tfidf_vectorizer_trainingset和tfidf_matrix_testset）。

#fitting tfidf transfrom for training data
tfidf_vectorizer_trainingset = tfidf_vectorizer.fit_transform(readfile(trainingdataDir)).toarray()

#tfidf transform the test set based on the training set
tfidf_matrix_testset = tfidf_vectorizer.transform(readfile(testingdataDir)).toarray().

但 threshold_function（）中的打印命令如下所示：

 The Mean of the mean of cosine similarity score for a normal Behaviour: nan
The standard deviation of the mean of cosine similarity score: nan
The threshold for normal behaviour should be (Mean - 3*standard deviation): nan

EDIT2 我发现 k_nearest_cosineMean 中的第一个值是 nan 。删除值后，我设法获得有效的计算。

Answer 1

我呼叫threshold_function() knearest_similarity(tfidf_matrix_testset)的第一行，但您从未定义tfidf_matrix_testset是什么。你也在第二行做到了。在第三行中，您使用第二行的输出。给tfidf_matrix_testset一个值。

函数没有返回任何python

1 个答案: