nums <- c(1, 2, 3, 4, 5)
# A comparison gives a logical vector, a mask
is_odd <- nums %% 2 == 1
# is_odd = TRUE FALSE TRUE FALSE TRUE
# The mask picks the elements
odd_items <- nums[is_odd]
# odd_items = 1 3 5
# Several conditions
middle <- nums[nums > 1 & nums < 5]
# middle = 2 3 4
cat("is_odd =", is_odd, "\n")
cat("odd_items =", odd_items, "\n")
cat("middle =", middle, "\n")