Creating a new variable with levels in R

Question

I am very much a novice to R and currently struggling to learn the language. What I am trying to do is create a new variable with three levels (if that makes sense). I am trying to show growth <=0%,<1%, and >=1% all in the same new variable (let me know if that is even possible).

So far I have tried this:

pincome$perctchng<- ifelse(pincome$perctchng<=0,ifelse(pincome$perctchng<1,
              ifelse(pincome$perctchng>=1,"level 1","level 2","level 3")))

This is the code that I attempted. I know that it is wrong, but any advice is the right direction is welcomed.

Thanks!

Answer 1

Nested ifelse statements are almost never the right answer. They're hard to read and fragile. Your goal is to transform a continuous value (the numeric values in perctchng ) into a categorical value ('level 1', etc). R's cut function is perfect for this:

pincome <- data.frame(perctchng = c(-2, -1, 0, 1, 2, 5))

  perctchng
1        -2
2        -1
3         0
4         1
5         2
6         5

pincome$level <- cut(pincome$perctchng, c(-Inf, 0, 1, Inf), c('level 1', 'level 2', 'level 3'))

  perctchng   level
1        -2 level 1
2        -1 level 1
3         0 level 1
4         1 level 2
5         2 level 3
6         5 level 3

Answer 2

Your solution is almost good your syntax is just not right :

library(dplyr)

pincome <- data.frame(perctchng = c(-2, -1, 0, 1, 2, 5))

pincome %>%
  mutate(perctchng_level = ifelse(perctchng <= 0, "level 1",
                            ifelse(perctchng < 1, "level 2",
                                   ifelse(perctchng >= 1, "level 3", NA))))

results :

  perctchng perctchng_level
1        -2         level 1
2        -1         level 1
3         0         level 1
4         1         level 3
5         2         level 3
6         5         level 3

Answer 3

A tidyverse solution:

pincome$perctchng<- ifelse(pincome$perctchng<=0,ifelse(pincome$perctchng<1, ifelse(pincome$perctchng>=1,"level 1","level 2","level 3")))

library(tidyverse)
pincome <- pincome %>%
           mutate(perctchng = case_when(perctchng <= 0 ~ "level 1",
                                        perctchng < 1 ~ "level 2",
                                        perctchng >= 1 ~ "level 3",
                                        TRUE ~ NA_character_)