Set up rowwise() and colwise() functions for use in .SD
Nobody has claimed this yet.
Assessment
- Difficulty
- 5/5
- Estimated time
- Over a week
- Newbie friendliness
- 20/100
Research direction
No files, tests, or implementation entry points are named. Start by reviewing the proposed rowwise(.SD, ) and colwise(.SD, ) examples and the listed row operations; done would require an agreed scope and working row- and column-wise implementations for lists and data.tables.
Written by the indexing model from the issue text.
Description
The idea is to implement all possible functions in C to directly operate on lists. To begin with, maybe:
- rowmins
- rowmaxs
- rowmeans
- rowsums
- rowvars
- rowsds
- ...
Implementations should be for both row- and column-wise for lists/data.tables.
This'll enable us to:
DT[, rowwise(.SD, <functions>)]
DT[, colwise(.SD, <functions>)]
This will:
- overcome the current limitation of
lapplywhich makes it tedious to aggregate using multiple functions. - provide both row- and col-wise operations for data.tables, where most common functions will be implemented and query optimised to use them automatically.
- Dominant language
- R
- Stars
- 3.9k
- Forks
- 1.1k
- Avg merge
- 14h 4m
- Merged PRs (30d)
- 4
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.
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