Create grouped dataframe by properties of a given column?

[phantom]

Would it have to do with how sortperm handles the by kwarg? If it’s handled the same way you mentioned here.

@rocco_sprmnt21

The function has this fingerprint searchsortedfirst(a, x; by=<transform>, lt=<comparison>, rev=false).
The comparison between the value to be searched for x and the candidate values a_i is done in the following way lt(by(x),by(a_i)) until the first a_i >=x is found.

Then could sortperm be computing f(data) multiple times to sort the data whereas with

@rocco_sprmnt21

 fdata=f.(data)
 spi=sortperm(fdata)

f.(data) is calculated just once?