我正在尝试在数据框的多个分组内查找不包括“NA”的多个列的平均值 airquality <- data.frame(City = c("CityA", "CityA","CityA", "CityB","CityB",...
I would like to transform a table like this (*): set.seed(1) mydata <- data.frame(ID=rep(1:4, each=3), R=rep(1:3, times=4), FIXED=rep(runif(4),...