R 选定行的列中值的总和

Question

我有以下数据集：

         Mark    Model      Sold
1       Skoda  Octavia     21125
2       Skoda    Fabia     19679
3        Opel    Astra     15282
4  Volkswagen     Golf     14190
5      Toyota    Yaris     14032
6      Toyota    Auris     12073
7        Ford    Focus     11126

我需要一个公式来汇总每个品牌的销售数量，以获得如下所示的结果：

         Mark   Total Sold
1       Skoda        40804
2        Opel        15282
3  Volkswagen        14190
4      Toyota        26105
5        Ford        11126

有人可以帮我吗？

Answer 1

我们可以按总和使用一个组。 在base R ，这可以通过aggregate来完成

aggregate(Sold ~ Mark, df1, sum)

---

或者用dplyr

library(dplyr)
df1 %>%
   group_by(Mark) %>%
   summarise(Total = sum(Sold))
# A tibble: 5 x 2
#  Mark       Total
#  <chr>      <int>
#1 Ford       11126
#2 Opel       15282
#3 Skoda      40804
#4 Toyota     26105
#5 Volkswagen 14190

数据

df1 <- structure(list(Mark = c("Skoda", "Skoda", "Opel", "Volkswagen", 
"Toyota", "Toyota", "Ford"), Model = c("Octavia", "Fabia", "Astra", 
"Golf", "Yaris", "Auris", "Focus"), Sold = c(21125L, 19679L, 
15282L, 14190L, 14032L, 12073L, 11126L)), 
class = "data.frame", row.names = c("1", 
"2", "3", "4", "5", "6", "7"))