knn算法实现，在给定新文本后，考虑在训练文本集中与该新文本距离最近（最相似）的 K 篇文本，根据这 K 篇文本所属的类别判定新文本所属的类别。-knn algorithm, given the new text, considering the text focused on the training of the new text with the closest (most similar) K-chapter text, according to the text of this article the category K determines the new text belongs.