Sklearn The Truth Value Of An Array With More Than One Element Is Ambiguous. Use A.any() Or A.all() Error

I'm trying out a code on training datasets that I saw online, but can't seem to resolve the error as mentioned. When I first ran the code, I get the above error as such: ValueError

Solution 1:

You are using check_cv wrong. According to the documentation:-

check_cv(cv=’warn’, y=None, classifier=False):

cv : int, 
     cross-validation generator or an iterable, optional

y : array-like, optional
    The target variable for supervised learning problems.

classifier : boolean, optional, defaultFalse
             Whether the task is a classification task, 
             in which case stratified KFold will be used

So it wants y and estimator in input. But you are providing X and y which is wrong. Change the below lines:

cv = check_cv(self.cv, X, y)
knn = KNeighborsClassifier(metric='precomputed', algorithm='brute')

to:

knn = KNeighborsClassifier(metric='precomputed', algorithm='brute')
cv = check_cv(self.cv, y, knn)

Note the order of lines.