mydata$group <- factor(mydata$group) ```🎲使用`sample()`函数随机抽取260个样本作为训练集,其余作为测试集: ```R sub <- sample(1:392, 260) train <- mydata test <- mydata ```🌳构建随机森林回归模型,并输出变量的重要性: ```R mydata.rf <- randomForest(group ~ ., data=train, i...