strange error message while using mutate and case_when to update a var-CodePudding

I have a df with 56 rows, and I want to update var PAV" base on tt`. It is very simple but I got very strange errors. Could anyone tell me what might be the reason?

df<-structure(list(tt = c(NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, 
                        NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, "Y", "Y", "Y", "Y", "Y", 
                        "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", 
                        "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", 
                        "Y", "Y", "Y", "Y", "Y"), PAV = structure(c("2", "2", "2", "2", 
                                                                    "2", "2", "3", "3", "3", "3", "3", "3", "3", "3", "3", "3", "3", 
                                                                    "3", "5", "5", "4", "4", "4", "4", "4", "4", "4", "4", "4", "4", 
                                                                    "4", "4", "4", "4", "4", "4", "4", "4", "4", "4", "4", "4", "4", 
                                                                    "4", "4", "4", "7", "7", "7", "7", "7", "7", "7", "7", "7", "7", 
                                                                    "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", "0", 
                                                                    "0", "0", "0", "0", "0", "", "", "", "", "", "", "", "", "", 
                                                                    "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", 
                                                                    "", "", "", "", "", "", "", "", "", "", "", "", ""), .Dim = c(56L, 
                                                                                                                                  2L))), class = "data.frame", row.names = c(NA, 56L))

df<- df %>% 
mutate(PAV=case_when(tt=="Y"~PAV))

The error code is: Error: Problem with mutate()columnPAV. i PAV = case_when(tt == "Y" ~ PAV). x tt == "Y" ~ PAV must be length 56 or one, not 112.

CodePudding user response：

The column 'PAV' is a matrix column. We may need to convert to two regular columns first and then loop across those columns to update the values

library(purrr)
library(dplyr)
df %>% 
  invoke(data.frame, .) %>%
  mutate(across(starts_with('PAV'), ~ case_when(tt %in% 'Y' ~ .x)))