queryverse / queryverse/CSVFiles.jl

Problem with nastring for non-numeric columns

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enhancement
Dominant language
Julia
Stars
52
Forks
12
Avg merge
18h 21m
Merged PRs (30d)
3

Description

Because the default nastring is NA there is a following problem:

  1. take a data structure that has e.g. String column with missing data in it;
  2. save it to disk using default parameters; missings get converted to NA on disk
  3. load it back and you have "NA" string where you earlier had missings

The same problem occurs with e.g. Char data.

While NA is a sensible default for numeric columns it is a bit confusing for non-numeric columns (and actually can lead to wrong results as it is fully possible to have NA string in data).

I think that it would be best to have an empty string for missings in non-numeric data.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in CSVFiles.jl by locating the default nastring handling for non-numeric columns and the save/load path. Add coverage for String and Char missing-value round trips with default parameters, and verify that existing numeric-column behavior remains unchanged.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
data
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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