Removing NA as a level from multiple variables

# Load in necessary libraries and set seed
set.seed(2025)
library(chcRne)
library(dplyr)

Applying remove.na.levels() to multiple variables

First, lets look at the levels of the different variables within the data frame na.as.lvl.

# Applying the levels function to all variables in the na.as.lvl data frame
sapply(na.as.lvl, levels) 
#>      Var1       Var2      
#> [1,] "Disagree" "Disagree"
#> [2,] "Agree"    "Agree"   
#> [3,] NA         NA

As we can see in the above output, both Var1 and Var2 have NA as a level. Now we apply the remove.na.levels to Var1 and Var2.

# List out all variable names of ordered factors
cols.with.na.lvls <- na.as.lvl %>% select(Var1, Var2) %>% names()

# Apply function
na.not.as.lvl <- na.as.lvl |>  mutate(across(all_of(cols.with.na.lvls), ~remove.na.levels(.x)))

Now that we have applied the function to the variables of interest, lets check and make sure NA is no longer a level in Var1 and Var2.

sapply(na.not.as.lvl, levels)
#>      Var1       Var2      
#> [1,] "Disagree" "Disagree"
#> [2,] "Agree"    "Agree"

Success! NA is no longer a level in Var1 and Var2.