CSV.write() won't take nothing values
You can use something
function to convert nothing
to whatever you want (e.g. missing
) like this:
something.(df, missing) |> CSV.write("aaa.txt")
The current reasoning behind the design not to support nothing
when writing a CSV file is given here.
I prefer the syntax of the CSV transform
argument:
CSV.write("filename.csv", df, transform=(col, val) -> something(val, missing))
From the CSV.write documentation
Posting this as a separate answer, hopefully to distinguish comments and gather clarifications if I am missing something important.