Logistic regression （逻辑回归）是当前业界比较常用的机器学习方法-Logistic regression (logistic regression) is more commonly used current industry machine learning methods

GridSearchCV用于设置PCA的维度，解决逻辑回归预测时，PCA维度降维问题。-The PCA does an unsupervised dimensionality reduction, while the logistic regression does the prediction. We use a GridSearchCV to set the dimensionality of the PCA