Recode categorical variable to binary (0/1)
Could someone help me regarding the use of ifelse.
I have a data.frame (dat) with a categorical variable/factor called Q1 (dat$Q1). dat$Q1 was coded as 1,2,3 or 4. I need to create a new column data$new1 based on the following rule:
if dat$Q1 == 3 then dat$new1 should be 1. otherwise, dat$new1 should be 0.
What is the most efficient way of doing this please?
Use ifelse as in:
dat$new1 <- ifelse(dat$Q1==3, 1, 0)
Just:
dat$new1 <- 0+(dat$Q1==3) # or use as.numeric(.)