Take a look at this
library("tidyverse")
set.seed(643046)
d <- tibble(DXCURREN = sample(x = 1:3, size = 20, replace = TRUE),
YEAR = str_c("/", sample(x = 1940:2020, size = 20, replace = TRUE)))
d %>%
mutate(CLASS = case_when(DXCURREN == 1 ~ "HC",
DXCURREN == 2 ~ "non-HC",
DXCURREN == 3 ~ "non-HC"),
YEAR = str_replace(string = YEAR,
pattern = "/",
replacement = ""))
Hope it helps! 