👀 Views: 5 💬 Answers: 1 📅 Created: 2025-05-31

r dplyr dataframe R

I'm refactoring my project and I'm performance testing and I've encountered a strange issue with I'm attempting to set up I'm working with R version 4.2.1 and using the `dplyr` package (version 1.0.7) to manipulate a data frame... I have a data frame containing a column with categorical values and I'm attempting to create a new column based on those values using `mutate` alongside `case_when`. However, I'm encountering unexpected NA values in the new column, and I'm not sure why this is happening. Here's a simplified version of my code: ```r library(dplyr) # Sample data frame my_data <- data.frame( category = c('A', 'B', 'C', 'D', 'E'), value = c(10, 20, 30, 40, 50) ) # Using mutate with case_when my_data <- my_data %>% mutate(new_category = case_when( category == 'A' ~ 'Alpha', category == 'B' ~ 'Beta', category == 'C' ~ 'Gamma', TRUE ~ NA_character_ # This should cover any other case )) ``` After running this code, I expect `new_category` to contain 'Alpha', 'Beta', 'Gamma', and NA for categories 'D' and 'E'. However, I am getting the following output: ``` category value new_category 1 A 10 Alpha 2 B 20 Beta 3 C 30 Gamma 4 D 40 <NA> 5 E 50 <NA> ``` The output looks fine, but I was expecting `new_category` for categories 'D' and 'E' to be `NA` due to the TRUE statement at the end of my `case_when`. Yet, they are returning `<NA>` which confuses me. I also noticed that when I use `na.omit(my_data)`, the rows for 'D' and 'E' are removed, which is not what I intended. I want to keep them as NA values. I've tried removing the `TRUE ~ NA_character_` line and directly assigning NA without it, but that resulted in errors. I also double-checked the values in `category` to ensure there are no leading or trailing spaces or special characters. Can anyone explain why I'm getting `<NA>` instead of NA, and what the best practice is for handling this situation in `dplyr`? I'm coming from a different tech stack and learning R. Any examples would be super helpful. Is there a simpler solution I'm overlooking? This is for a REST API running on Debian. Is there a better approach? Thanks for your help in advance!