R中使用purrr或dplyr如何按Group分组累加指定Type的Quantity

实现方案 #

你可以直接用dplyr的基础分组汇总逻辑完成需求，无需用到复杂的purrr::map或across函数，代码如下：

1. 构造测试数据

library(tidyverse)

df <- tibble(
  Group = c(1,1,1,1,2,2,2,2),
  Type = c("A", "B", "C", "D", "A", "B", "C", "E"),
  Quantity = c(5,8,9,10,7,6,4,5)
)

2. 核心处理代码

df_result <- df %>%
  # 将需要合并的B、C类型统一替换为新标识
  mutate(Type = ifelse(Type %in% c("B", "C"), "B + C", Type)) %>%
  # 按分组和新的Type字段汇总Quantity
  group_by(Group, Type) %>%
  summarise(Quantity = sum(Quantity), .groups = "drop")

输出结果

# A tibble: 6 × 3
  Group Type  Quantity
  <dbl> <chr>    <dbl>
1     1 A            5
2     1 B + C       17
3     1 D           10
4     2 A            7
5     2 B + C       10
6     2 E            5

内容的提问来源于stack exchange，提问作者Dmando