R语言,请问怎么在数据框新增一列为前两列之比?答:save1<-data.frame(Weight,Height);//身高体重数据写入文本文件 write.csv(save1, file = "foo1.csv", sep = ",", col.names = TRUE);//读取数据至data数据框 foo<-read.csv("foo1.csv", header=T, sep=",");//data数据框新增一列bmi变量 data.frame(Weight,Height,BMI=Weight/Heig...