在R中为学生入学数据框追加指定汇总行的更优方法

原始数据与需求 #

你的原始数据框定义如下：

df <- structure(list(Grade = c("PK3", "PK4", "KG", "Grade 1", "Grade 2", 
"Grade 3", "Grade 4", "Grade 5", "Grade 6", "Grade 7", "Grade 8", 
"Grade 9", "Grade 10", "Grade 11", "Grade 12", "Ungraded"), Enrolled = c(4967, 
6481, 7378, 7041, 6760, 6590, 6473, 6191, 5790, 5693, 5614, 7254, 
4951, 4250, 3792, 238)), row.names = c(NA, -16L), class = c("tbl_df", 
"tbl", "data.frame"))

需求是在数据框末尾追加两行：

• k_12_total：K-12年级（排除PK3、PK4）的总入学人数
• pk_12_total：PK-12年级（所有行）的总入学人数

你当前的实现（冗长版） #

df2 = df %>% filter(Grade != "PK3" & Grade != "PK4") %>%
  adorn_totals(where="row", name="k_12_total") %>%
  filter(Grade == "k_12_total")
df = rbind(df, df2)

df2 = df %>% filter(Grade != "k_12_total") %>%
  adorn_totals(where="row", name="pk_12_total") %>%
  filter(Grade == "pk_12_total")
df = rbind(df, df2)

更优的实现方式 #

方法1：用dplyr直接计算+一次性合并

直接生成两个合计行，再用bind_rows合并，避免多次修改原数据框：

library(dplyr)

# 生成K-12合计行
k12_total <- df %>%
  filter(!Grade %in% c("PK3", "PK4")) %>%
  summarize(Grade = "k_12_total", Enrolled = sum(Enrolled))

# 生成PK-12合计行
pk12_total <- df %>%
  summarize(Grade = "pk_12_total", Enrolled = sum(Enrolled))

# 合并所有数据
df_final <- bind_rows(df, k12_total, pk12_total)

方法2：用janitor简化取合计行的操作

如果坚持用janitor包，可以用slice_tail直接取最后一行的合计，替代filter：

library(janitor)
library(dplyr)

k12_total <- df %>%
  filter(!Grade %in% c("PK3", "PK4")) %>%
  adorn_totals("row", name = "k_12_total") %>%
  slice_tail(n = 1)

pk12_total <- df %>%
  adorn_totals("row", name = "pk_12_total") %>%
  slice_tail(n = 1)

df_final <- bind_rows(df, k12_total, pk12_total)

方法3：最紧凑的链式写法

不需要单独创建中间变量，直接在bind_rows里完成两个合计的计算：

library(dplyr)

df_final <- df %>%
  bind_rows(
    # 计算K-12合计
    summarize(., Grade = "k_12_total", Enrolled = sum(Enrolled[!Grade %in% c("PK3", "PK4")])),
    # 计算PK-12合计
    summarize(., Grade = "pk_12_total", Enrolled = sum(Enrolled))
  )

以上三种方法都比你原来的代码更简洁直观，避免了重复的filter和rbind操作，同时保持逻辑清晰。

内容的提问来源于stack exchange，提问作者user3710004