Problem：Develop a k-NN classifier with Euclidean distance and simple votingPerform 5-fold cross validation, find out which k performs the best (in terms of accuracy)Use PCA to reduce the dimensi

接着统计学习中knn算法实验（1）的内容Problem：Explore the data before classification using summary statistics or visualizationPre-process the data (such as denoising, normalization, feature selection, …) Try ot