How to simplify handling with nested ifelse() structures in base R?

Question

I\'m facing nested ifelse() structures:

df1$var <- ifelse(x < a, u, ifelse(x < b, v, ifelse(x < c, w, ...)))

whereby t

Answer 1

You could use case_when from the dplyr library:

df1$y <- case_when(
    x == 1 ~ "s",
    x == 2 ~ "t",
    x == 3 ~ "u",
    x == 4 ~ "v",
    TRUE ~ "w"
)

Note that the final case above (TRUE) is the blanket else condition which will catch all cases not matching any earlier conditions.