Nested if-else loops in R

Question

I have a data frame named \"crimes\" which contains a \"pre_rate\" column that denotes the crime rate before a certain law is implemented. I would like to put each rate in a

Answer 1

Instead of multiple nested ifelse(), a non-equi join and update on join can be used

# OP's sample data set with one out-of-bounds value appended
crimes = data.frame(pre_rate = c(0.27, 1.91, 2.81, 3.21, 4.80, 1.0))   

library(data.table)
# specify categories, lower, and upper bounds
bounds <- data.table(
  cat = 1:5,
  lower = c(0.26, 1.04, 2.03, 3.10, 4.2),
  upper = c(0.87, 1.94, 2.96, 3.82, 11)
)
# non-equi join and update on join
setDT(crimes)[bounds, on = .(pre_rate > lower, pre_rate < upper), rate_category := cat][]

   pre_rate rate_category
1:     0.27             1
2:     1.91             2
3:     2.81             3
4:     3.21             4
5:     4.80             5
6:     1.00            NA

Note that pre-rate values which are outside of any of the given intervals do get a NA rate_category automatically.