If supplying data (that can be either string or numeric) via CSVs, what's a good strategy for marking that a value is missing?
- Some non-empty sentinel, like
- Some non-empty sentinel, but quoted like
- The empty string, e.g. in the CSV the value will be 0 characters long.
- The quoted empty string
- Something else / depending on case?
If it makes a difference, would like the CSVs to behave reasonably when read using R readr, Python Pandas, and Excel.