How to add a column that contains specific values when criteria is met?

Question

I have a dataframe:

tibble{
x = c(1,2,3)
y = c(0,2,4)
}

I want to add a NEW variable "z" that will be:

z = c("Lower", "Equal", "Higher")

I was thinking about using a for loop but I'm not sure if that's the most efficient/correct way.

Answer 1

The new variable in the dataset can be created with sign after taking the difference of 'x' and 'y', get the sign values, convert it to factor with levels and corresponding labels specified

library(dplyr)
df1 %>% 
 mutate(z = factor(sign(x - y), levels = c(-1, 0, 1), 
   c('Lower', "Equal", 'Higher')))

---

Or an option with case_when

df1 %>%
  mutate(tmp = x - y,
         z = case_when(tmp >0 ~ 'Higher', tmp < 0 ~ 'Lower',
             TRUE ~ 'Equal'), tmp = NULL)

data

df1 <- tibble(
    x = c(1,2,3),
    y = c(0,2,4))

Answer 2

A base R option

within(df,z <- c("Lower", "Equal", "Higher")[sign(y-x)+2])

which gives

# A tibble: 3 x 3
      x     y z     
  <dbl> <dbl> <chr>
1     1     0 Lower
2     2     2 Equal
3     3     4 Higher