How to delete "" from factor levels?

Question

My gender variable is a factor with three levels: "", "Female", and "Male". How can I remove "" from its levels?

Answer 1

You can use

levels(all_trips_v2$gender)[1] <- NA

---

Here is a test:

x <- factor(c("", "F", "M"))

levels(x)
#[1] ""  "F" "M"

## the first level is ""; reset it to NA 
levels(x)[1] <- NA

x
#[1] <NA> F    M   
#Levels: F M

levels(x)
#[1] "F" "M"