Say I have read in my files like this

using CSVFiles

@time a = load("c:/data/AirOnTimeCSV/airOT199302.csv", type_detect_rows = 2000)

Is there a way to iterate through the columns without converting it to DataFrame first (cos it's slow)?

E.g. if I did convert to DataFrame then I can do

adf = DataFrame(a)
for c in eachcol(adf)
   # do something to c, like serialize to disk.
end