应用家庭函数不适用于group_by()，但适用于select()

Question

我是R的新手，面临着奇怪的问题。

我试图为每个字符变量创建多个情节，以计数退出变量。

df_churn

gender  geography exited
<chr>   <chr>     <fctr>

Female  France  Churn       
Female  Spain   Remain      
Female  France  Churn       
Female  France  Remain      
Female  Spain   Remain      
Male    Spain   Churn       
Male    France  Remain      
Female  Germany Churn       
Male    France  Remain      
Male    France  Remain

甚至在我开始在group_by()中绘图之前，我就发现了lapply()的错误。

  lapply(c("geography","gender"), FUN = function(feature){
    df_churn %>% 
      group_by(feature, exited) %>%
      count()
  })

如果使用的是select()而不是group_by()，那么它就能工作：

  lapply(c("geography","gender"), FUN = function(feature){
    df_churn %>% 
      select(feature, exited) %>% 
      head()
  })

#------------------output-------------#
geography exited
<chr>     <fctr>

France  Churn           
Spain   Remain          
France  Churn           
France  Remain          
Spain   Remain          
Spain   Churn


gender exited
<chr>  <fctr>

Female  Churn           
Female  Remain          
Female  Churn           
Female  Remain          
Female  Remain          
Male    Churn

如何为group_by()修复这个问题?

我无法理解apply的家庭工作，以及enquous，rlang/ functional programming在r中的工作，这会使重复工作更容易。相反，这一切有时真的让人沮丧，

也将感谢任何良好的学习链接，以及他们。

谢谢！！

Answer 1

您的代码使用select而不是group_by的原因是select使用字符值，而不是group_by。

1. 修复此使用sym与!! :

library(dplyr)

lapply(c("geography","gender"), FUN = function(feature){
  df_churn %>% 
    group_by(!!sym(feature), exited) %>%
    count()
})

1. 和.data :

lapply(c("geography","gender"), FUN = function(feature){
  df_churn %>% 
    group_by(.data[[feature]], exited) %>%
    count()
})

1. 和across :

lapply(c("geography","gender"), FUN = function(feature){
  df_churn %>% 
    group_by(across(c(feature, "exited"))) %>%
    count()
})

1. 和get :

lapply(c("geography","gender"), FUN = function(feature){
  df_churn %>% 
    group_by(get(feature), exited) %>%
    count()
})