r - 如何将重复值分组为单个值并在 R 中提取与该列值关联的值？

Question

我有一个看起来像这样的数据框:

df <- data.frame(
  Location = c("buildinga", "buildinga", "buildinga", "buildingb", "buildingb", "buildingb", "buildingc", "buildingc", "buildingc),
  Category   = c(candy, candy, snacks, candy, snacks, soda, soda, candy, soda)
  Calories   = 200, 250, 150, 180, 200, 80, 140, 200, 210)
)

我想按单个建筑物对“位置”进行分组，并为每个位置提取相应的值(因此建筑物 a、b 和 c 具有糖果、零食和苏打水的总卡路里)。

我尝试执行 group_by(location) %>% summarize(count(n=()) 但这仍然给了我每个位置。我想删除重复的位置但不是'类别'或'卡路里'。

Answer 1

使用 dplyr，您可以group_by 您的数据并计算每个类别中的卡路里。

library(dplyr)
df %>%
  group_by(Location, Category) %>%
  summarise(Count = sum(Calories))

# A tibble: 7 x 3
# Groups:   Location [3]
  Location  Category Count
  <fct>     <fct>    <dbl>
1 buildinga candy      450
2 buildinga snacks     150
3 buildingb candy      180
4 buildingb snacks     200
5 buildingb soda        80
6 buildingc candy      200
7 buildingc soda       350

是您要找的吗？

数据

您的数据示例有一些拼写错误，这是我使用的:

df <- data.frame(
  Location = c("buildinga", "buildinga", "buildinga", "buildingb", "buildingb", "buildingb", "buildingc", "buildingc", "buildingc"),
  Category   = c("candy", "candy", "snacks", "candy", "snacks", "soda", "soda", "candy", "soda"),
  Calories   = c(200, 250, 150, 180, 200, 80, 140, 200, 210)
)