Question about reshaping array size for KNN Classifiers
Seems you are making two mistakes -
Reshaping dim. is mismatched with the size i.e. 10 != 3X3
Dim in train and test are different. Trained of 5 features and testing on 4 features.
What I will suggest -
 You would be aware of your features count - let's say N
 then reshape using reshape(-1,N). It will automatically decide the first dim.
x = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
N=2
x.reshape(-1,N)