[ENH] Conditional_join on an equi-join with numba (#1267)

* skeleton

* partial implementation

* minor edits

* add comments

* fix notebook

* Update conditional_join.ipynb

* add changelog

* updates

* update changelog

* add more tests

* shortcut for monotonic increasing groups

* use 0/1 for counter check for monotonicity

* fix test failure

* [DEPR] deprecate `pivot_wider` (#1263)

* simplify logic

* minor updates

* changelog

* fix userwarning on then function

---------

Co-authored-by: Eric Ma <[email protected]>

* fix range count

* remove irrelevant imports

* fix test fail

* Update CHANGELOG.md

* Update CHANGELOG.md

* fix test failure

* remove caching

* add force parameter

* update docstrings

* fix failing test

* remove strict eq join check

---------

Co-authored-by: samuel.oranyeli <[email protected]>
Co-authored-by: Eric Ma <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -12,8 +12,8 @@
 -   [DEPR] Add deprecation warnings for `process_text`, `rename_column`, `rename_columns`, `filter_on`, `remove_columns`, `fill_direction`. Issue #1045 @samukweku
 -   [ENH] `pivot_longer` now supports named groups where `names_pattern` is a regular expression. A dictionary can now be passed to `names_pattern`, and is internally evaluated as a list/tuple of regular expressions. Issue #1209 @samukweku
 -   [ENH] Improve selection in `conditional_join`. Issue #1223 @samukweku
--   [ENH] Performance improvement for range joins in `conditional_join`, when `use_numba = False`. PR #1256 @samukweku
 -   [ENH] Add `col` class for selecting columns within an expression. Currently limited to use within `conditional_join`. PR #1260 @samukweku.
+-   [ENH] Performance improvement for range joins in `conditional_join`, when `use_numba = False`. Performance improvement for equi-join and a range join, when `use_numba = True`, for many to many join with wide ranges. PR #1256, #1267 @samukweku
 -   [DEPR] Add deprecation warning for `pivot_wider`. Issue #1045 @samukweku
 -   [BUG] Fix string column selection on a MultiIndex. Issue #1265. @samukweku