变异和/或总结动态数目的列

Question

在前面的一个问题中，我希望用动态数量的事例执行case_when。解决方案是使用parse_exprs和！！！。我正在寻找一个类似的解决方案，以变异/总结与动态数量的列。

考虑以下数据集。

library(dplyr)
library(rlang)
data(mtcars)
mtcars = mtcars %>%
  mutate(g2 = ifelse(gear == 2, 1, 0),
         g3 = ifelse(gear == 3, 1, 0),
         g4 = ifelse(gear == 4, 1, 0))

answer = mtcars %>%
  summarise(sum_g2 = sum(g2),
            sum_g3 = sum(g3),
            sum_g4 = sum(g4))

columns_to_sum = c("g2","g3","g4")

formulas = paste0("sum_",columns_to_sum," = sum(",columns_to_sum,")")

answer = mtcars %>%
  summarise(!!!parse_exprs(formulas))

Answer 1

DPLYR 1.0.0以来的一个选择是：

mtcars %>%
 summarise(across(all_of(columns_to_sum), sum, .names = "sum_{col}"))

  sum_g2 sum_g3 sum_g4
1      0     15     12