I would like to recreate the ifelse syntax from R in Julia and am not sure the best way to do that.

In my example I have a panel of developments and an array of developments that did receive a treatment

developments = 1:10000
years = 1:20
# panel of developments, each development observed for 20 years
data =rename!(DataFrame( (Iterators.product(developments, years)) ), [:development, :year])
# randomly assign 5000 developments to treatment
treated = sample(developments,Int(length(developments) / 2), replace = false )

# make a new column that specifies if that development ever received treatment
???

In R this would be

data$treated = ifelse(data$development %in% treated,1,0)

I can do

data[!, :treated] = [x in treated for x in data[!,:development]]

But I don't know how to neatly generalize this to handle multiple if-else statements similar to the R function case_when, or how to change the variable to be "treated" and "not treated" instead of true/false.

Thanks!