Difference between factor and as factor in R programming

Question

I recently got into these lines

x <- as.factor(rep(1:4, 2))
x
# [1] 1 2 3 4 1 2 3 4 
# Levels: 1 2 3 4

But if I do

x <- factor(rep(1:4, 2)) 

that gives me the same result. So what is the difference between factor and as.factor? I get how factor is pulling same numbers out and making them levels, but I don't get what the exact differences are between factor and as.factor.

Answer 1

Hey @Ali, as.factor is a wrapper for factor, but it allows quick return if the input vector is already a factor: