将列名作为字符串传递给group_by并在dplyr中汇总

Question

使用dplyr启动版本0.7时,不推荐使用以下划线结尾的方法(例如summarize_group_by_),因为我们应该使用quosures.

请参阅:https: //cran.r-project.org/web/packages/dplyr/vignettes/programming.html

我试图使用quo和!!实现以下示例

工作范例:

df <- data.frame(x = c("a","a","a","b","b","b"), y=c(1,1,2,2,3,3), z = 1:6)

lFG <- df %>% 
   group_by( x,y) 
lFG %>% summarize( min(z))

但是,在这种情况下,我需要实现要分组的列,并将汇总指定为字符串.

cols2group <- c("x","y")
col2summarize <- "z"

我怎样才能得到与上述相同的例子呢？

Answer 1

从dplyr1.0.0 开始您可以使用across：

library(dplyr)

cols2group <- c("x","y")
col2summarize <- "z"

df %>%
  group_by(across(all_of(cols2group))) %>%
  summarise(across(all_of(col2summarize), min)) %>%
  ungroup

#   x       y     z
#  <chr> <dbl> <int>
#1 a         1     1
#2 a         2     3
#3 b         2     4
#4 b         3     5

Answer 2

为此,您现在可以使用_at动词的版本

df %>%  
  group_by_at(cols2group) %>% 
  summarize_at(.vars = col2summarize, .funs = min)