Combining mutate, across, and as_date('yyyymmdd') results in all NA

January 4, 2024

I’m trying to combine mutate, across, and as_date, including the format argument in as_date. This is resulting in all NA values, as shown below.

library(tidyverse)
library(tis)

holidays(2023) %>% 
  data.frame() %>% 
  set_names('holiday_date') %>% 
  rownames_to_column() %>%
  pivot_wider(names_from = rowname,values_from = holiday_date) %>% 
  mutate(across(everything(), as.character)) %>%
  mutate(across(everything(), 
                #as_date                      # WORKS
                ~as_date(.,format="yyyymmdd") # DOESN'T WORK
  ))

This results in

# A tibble: 1 × 10
  NewYears MLKing GWBirthday Memorial Juneteenth Independence Labor  Columbus Thanksgiving
  <date>   <date> <date>     <date>   <date>     <date>       <date> <date>   <date>      
1 NA       NA     NA         NA       NA         NA           NA     NA       NA          
# ℹ 1 more variable: Christmas <date>

If I swap the commented out as_date line (labelled "WORKS") for the ~as_date line ("DOESN'T WORK"), I get the expected result, sans the desired formatting:

# A tibble: 1 × 10
  NewYears   MLKing     GWBirthday Memorial   Juneteenth Independence Labor      Columbus   Thanksgiving
  <date>     <date>     <date>     <date>     <date>     <date>       <date>     <date>     <date>      
1 2023-01-02 2023-01-16 2023-02-20 2023-05-29 2023-06-19 2023-07-04   2023-09-04 2023-10-09 2023-11-23  
# ℹ 1 more variable: Christmas <date>

Can someone tell me what is going wrong here and how to obtain the desired result?

>Solution :

when you used pivot_wider() and then applied mutate(across(...)), the column types got converted to character format, hence the problem with the date conversion with as_date with the format argument.

instead, use mutate(across(...)) directly after pivot_wider() to convert the columns to character, and then use another mutate(across(...)) to convert them to dates. you can specify your own desired format.

holidays(2023) %>% 
  data.frame() %>% 
  set_names('holiday_date') %>% 
  rownames_to_column() %>%
  pivot_wider(names_from = rowname, values_from = holiday_date) %>% 
  mutate(across(everything(), as.character)) %>%
  mutate(across(everything(), as_date)) %>%  # Convert to dates without format
  mutate(across(everything(), 
                ~as_date(., format = "%Y-%m-%d")))  # Convert to dates with the desired format