Drop MultiIndex levels by level _number_, not name.
(self, levnums: list[int])
| 2302 | |
| 2303 | @final |
| 2304 | def _drop_level_numbers(self, levnums: list[int]): |
| 2305 | """ |
| 2306 | Drop MultiIndex levels by level _number_, not name. |
| 2307 | """ |
| 2308 | |
| 2309 | if not levnums and not isinstance(self, ABCMultiIndex): |
| 2310 | return self |
| 2311 | if len(levnums) >= self.nlevels: |
| 2312 | raise ValueError( |
| 2313 | f"Cannot remove {len(levnums)} levels from an index with " |
| 2314 | f"{self.nlevels} levels: at least one level must be left." |
| 2315 | ) |
| 2316 | # The two checks above guarantee that here self is a MultiIndex |
| 2317 | self = cast("MultiIndex", self) |
| 2318 | |
| 2319 | new_levels = list(self.levels) |
| 2320 | new_codes = list(self.codes) |
| 2321 | new_names = list(self.names) |
| 2322 | |
| 2323 | for i in levnums: |
| 2324 | new_levels.pop(i) |
| 2325 | new_codes.pop(i) |
| 2326 | new_names.pop(i) |
| 2327 | |
| 2328 | if len(new_levels) == 1: |
| 2329 | lev = new_levels[0] |
| 2330 | |
| 2331 | if len(lev) == 0: |
| 2332 | # If lev is empty, lev.take will fail GH#42055 |
| 2333 | if len(new_codes[0]) == 0: |
| 2334 | # GH#45230 preserve RangeIndex here |
| 2335 | # see test_reset_index_empty_rangeindex |
| 2336 | result = lev[:0] |
| 2337 | else: |
| 2338 | res_values = algos.take(lev._values, new_codes[0], allow_fill=True) |
| 2339 | # _constructor instead of type(lev) for RangeIndex compat GH#35230 |
| 2340 | result = lev._constructor._simple_new(res_values, name=new_names[0]) |
| 2341 | else: |
| 2342 | # set nan if needed |
| 2343 | mask = new_codes[0] == -1 |
| 2344 | result = new_levels[0].take(new_codes[0]) |
| 2345 | if mask.any(): |
| 2346 | result = result.putmask(mask, np.nan) |
| 2347 | |
| 2348 | result._name = new_names[0] |
| 2349 | |
| 2350 | return result |
| 2351 | else: |
| 2352 | from pandas.core.indexes.multi import MultiIndex |
| 2353 | |
| 2354 | return MultiIndex( |
| 2355 | levels=new_levels, |
| 2356 | codes=new_codes, |
| 2357 | names=new_names, |
| 2358 | verify_integrity=False, |
| 2359 | ) |
| 2360 | |
| 2361 | # -------------------------------------------------------------------- |
no test coverage detected