PCA

代码说明：

  主成分分析是把原来多个变量划为少数几个综合指标的一种统计分析方法。 从数学角度来看，这是一种降维处理技术。(Principal component analysis (PCA) is a statistical analysis method that divides a number of variables into a few comprehensive indexes.From a mathematical point of view, this is a kind of dimensionality reduction technology.)