Question

I’m trying to write an R script to evaluate different expressions based on fitting a value within ranges. The idea is that if Length is within one range, it will get evaluated one way, and if it’s in a longer range it will get evaluated differently.

I can make this work with if/else statements, but it’s pretty ugly, and I’m sure there must be a better way… here’s code that works.

Length=8.2

if (Length<1) 
    mode="Walk"
else if (1<=Length & Length <5)
    mode="bike" 
else if (5<=Length & Length <10)
    mode="drive"
else if (Length>=10)
    mode="fly"

I’ve been trying to make something work with the switch function, but it seems to only work with text or integers… is there a way to have a switch statement that conducts evaluations at each case such as this?

Length=3.5

switch(Length,
       (Length<1)  mode="Walk"
       (1<=Length & Length <5)  mode="bike"
       (5<=Length & Length <10)  mode="drive"
       (Length=>10)  mode="fly"
)

Answer 1

Here is a similar answer to Josh’s, but using findInterval:

Length <- 0:11

cuts <- c(-Inf, 1, 5, 10, Inf)
labs <- c("Walk", "bike", "drive", "fly")

labs[findInterval(Length, cuts)]
# [1] "Walk"  "bike"  "bike"  "bike"  "bike"  "drive" "drive"
# [8] "drive" "drive" "drive" "fly"   "fly"

You can also use nested ifelse statements, it’s a matter of taste:

ifelse(Length < 1,  "Walk",
ifelse(Length < 5,  "bike",
ifelse(Length < 10, "drive",
                    "fly")))
# [1] "Walk"  "bike"  "bike"  "bike"  "bike"  "drive" "drive"
# [8] "drive" "drive" "drive" "fly"   "fly"