r - 如何创建列值为 TRUE 的列名列表列

Question

我有一些多选问题的调查数据，这些数据与每个可能选择的列一起输出，填充了 TRUE/FALSE 值，例如

library(dplyr)

dat <- tribble(
  ~name, ~state, ~onions, ~`sweet potatoes`, ~garlic,
  "Tom", "WV", TRUE, FALSE, TRUE,
  "Larry", "NC", FALSE, TRUE, FALSE,
  "Beth", "NY", TRUE, TRUE, TRUE
)

dat

#>   name  state onions `sweet potatoes` garlic
#>   <chr> <chr> <lgl>  <lgl>            <lgl> 
#> 1 Tom   WV    TRUE   FALSE            TRUE  
#> 2 Larry NC    FALSE  TRUE             FALSE 
#> 3 Beth  NY    TRUE   TRUE             TRUE  

如何创建包含受访者回答“TRUE”的列名称的列表列？
类似于 https://stackoverflow.com/a/9508203/1009730
我已经尝试了几个关于主题的变体

dat %>%
  rowwise() %>%
  mutate(fav_foods = list(names(which(~ is.logical(.x) && .x))))

这给出了错误:

Error: Problem with mutate() input fav_foods. x argument to 'which' is not logical i Input fav_foods is list(names(which(~is.logical(.x) && .x))). i The error occurred in row 1.

Answer 1

添加 purrr ，你可以这样做:

dat %>%
 mutate(fav_foods = pmap_chr(across(where(is.logical)), ~ toString(names(c(...))[which(c(...))])))

  name  state onions `sweet potatoes` garlic fav_foods                     
  <chr> <chr> <lgl>  <lgl>            <lgl>  <chr>                         
1 Tom   WV    TRUE   FALSE            TRUE   onions, garlic                
2 Larry NC    FALSE  TRUE             FALSE  sweet potatoes                
3 Beth  NY    TRUE   TRUE             TRUE   onions, sweet potatoes, garlic

或者，如果您需要将其作为列表:

dat %>%
 mutate(fav_foods = pmap(across(where(is.logical)), ~ names(c(...))[which(c(...))]))

  name  state onions `sweet potatoes` garlic fav_foods
  <chr> <chr> <lgl>  <lgl>            <lgl>  <list>   
1 Tom   WV    TRUE   FALSE            TRUE   <chr [2]>
2 Larry NC    FALSE  TRUE             FALSE  <chr [1]>
3 Beth  NY    TRUE   TRUE             TRUE   <chr [3]>