如何按行和列彙總數據R

Question

我有以下問題。我有一個表至極數據如下：

，並希望建立這樣一個總結：

在Excel這件事的簡單的數據透視表，但如何做到這一點R中？

Answer 1

library(dplyr) 
cardata <- data.frame(country = c("poland", "germany", "austria", 
           "poland","poland", "austria", 
           "germany","germany"), 
        car = c("Fiat", "Fiat", "BMW", "Fiat", "BMW", 
          "Toyota", "Toyota", "Toyota"), 
        Age = c(5, 4, 2, 6, 6, 2, 1, 8), 
        Km = c(12e4, 10e4, 22e3, 14e4, 15e4, 52e3, 21e3, 22e4)) 

cardata %>% 
group_by(country, car) %>% 
summarise(AvgAge = mean(Age), 
      AvgKm = mean(Km))