Commit Graph

2 Commits

Author SHA1 Message Date
Dmitry S
95320f3f5b (core) Update documentation for lookup/find/prevnext for the Help Center
Summary: Documentation in https://github.com/gristlabs/grist-help/ is built using `./build-functions.sh`, and the current version (as updated and landed in https://github.com/gristlabs/grist-help/pull/368) already reflects the changes in this diff.

Test Plan: No changes to functionality, only documentation comments.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D4306
2024-08-12 12:50:44 -04:00
Dmitry S
f0d0a07295 (core) Implement PREVIOUS/NEXT/RANK and lookupRecords().find.* methods.
Summary:
- `lookupRecords()` now allows efficient search in sorted results, with
  the syntax  `lookupRecords(..., order_by="-Date").find.le($Date)`. This will find the record with the nearest date that's <= `$Date`.
- The `find.*` methods are `le`, `lt`, `ge`, `gt`, and `eq`. All have O(log N) performance.
- `PREVIOUS(rec, group_by=..., order_by=...)` finds the previous record to rec, according to `group_by` / `order_by`, in amortized O(log N) time. For example, `PREVIOUS(rec, group_by="Account", order_by="Date")`.
- `PREVIOUS(rec, order_by=None)` finds the previous record in the full table, sorted by the `manualSort` column, to match the order visible in the unsorted table.
- `NEXT(...)` is just like `PREVIOUS(...)` but finds the next record.
- `RANK(rec, group_by=..., order_by=..., order="asc")` returns the rank of the record within the group, starting with 1. Order can be `"asc"` (default) or `"desc"`.
- The `order_by` argument in `lookupRecords`, and the new functions now supports tuples, as well as the "-" prefix to reverse order, e.g. `("Category", "-Date")`.
- New functions are only available in Python3, for a minor reason (to support keyword-only arguments for `group_by` and `order_by`) and also as a nudge to Python2 users to update.

- Includes fixes for several situations related to lookups that used to cause quadratic complexity.

Test Plan:
- New performance check that sorted lookups don't add quadratic complexity.
- Tests added for lookup find.* methods, and for PREVIOUS/NEXT/RANK.
- Tests added that renaming columns updates `order_by` and `group_by` arguments, and attributes on results (e.g. `PREVIOUS(...).ColId`) appropriately.
- Python3 tests can now produce verbose output when VERBOSE=1 and -v are given.

Reviewers: jarek, georgegevoian

Reviewed By: jarek, georgegevoian

Subscribers: paulfitz, jarek

Differential Revision: https://phab.getgrist.com/D4265
2024-07-17 12:00:55 -04:00