Clojurians Log v2

First thoughts:

user> (require '[tech.v3.dataset :as ds])
nil
user> (slurp "t.csv")
"exp,start\nABC,1738558800000000000"
user> (def ds (ds/->dataset "t.csv"))
#'user/ds
user> ds
t.csv [1 2]:

| exp |               start |
|-----|--------------------:|
| ABC | 1738558800000000000 |
user> (map meta (ds/columns ds))
({:categorical? true, :name "exp", :datatype :string, :n-elems 1}
 {:name "start", :datatype :int64, :n-elems 1})
user> (ds/row-map ds (fn [{:strs [start]}]
                       (let [i (java.time.Instant/ofEpochSecond (/ start 1000000000)
                                                                (rem start 1000000000))]
                         {"inst" i
                          "date" (java.util.Date/from i)})))
t.csv [1 4]:

| exp |               start |                 inst |                         date |
|-----|--------------------:|----------------------|------------------------------|
| ABC | 1738558800000000000 | 2025-02-03T05:00:00Z | Sun Feb 02 22:00:00 MST 2025 |

Thanks Harold! Since the column is read natively as an :int64 , I was hoping to be able to leverage one of the packing formats to avoid actually touching the data. Not sure if that's possible.

You're welcome. My gut is that'd be very unlikely to be worth it. More flexible this way, and if performance became a concern (e.g., you have 10B+ rows of this every day) then there'd be bigger wins elsewhere (switching serialization formats, maybe).