Rdatatable / Rdatatable/data.table
[R-Forge #4914] Grouping could include unused factor levels while computing j (like `tapply` does)
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feature request
- Dominant language
- R
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Description
Submitted by: Arun ; Assigned to: Nobody; R-Forge link
This SO question explains the issue quite nicely!
http://stackoverflow.com/questions/18866796/empty-factors-in-by-data-table#18866796
Thanks to Asayat for reporting it.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reading the linked Stack Overflow question and the R-Forge report to understand the expected handling of unused factor levels during grouping. Then locate the relevant grouping and j evaluation paths in data.table and add regression coverage showing the desired tapply-like result.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- r
- Domain
- data
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100