from __future__ import annotations from functools import wraps from sys import getsizeof from typing import ( TYPE_CHECKING, Any, Callable, Collection, Generator, Hashable, Iterable, List, Literal, Sequence, Tuple, cast, ) import warnings import numpy as np from pandas._config import get_option from pandas._libs import ( algos as libalgos, index as libindex, lib, ) from pandas._libs.hashtable import duplicated from pandas._typing import ( AnyAll, AnyArrayLike, Axis, DropKeep, DtypeObj, F, IgnoreRaise, IndexLabel, Scalar, Shape, npt, ) from pandas.compat.numpy import function as nv from pandas.errors import ( InvalidIndexError, PerformanceWarning, UnsortedIndexError, ) from pandas.util._decorators import ( Appender, cache_readonly, doc, ) from pandas.util._exceptions import find_stack_level from pandas.core.dtypes.cast import coerce_indexer_dtype from pandas.core.dtypes.common import ( ensure_int64, ensure_platform_int, is_categorical_dtype, is_extension_array_dtype, is_hashable, is_integer, is_iterator, is_list_like, is_object_dtype, is_scalar, pandas_dtype, ) from pandas.core.dtypes.dtypes import ExtensionDtype from pandas.core.dtypes.generic import ( ABCDataFrame, ABCDatetimeIndex, ABCTimedeltaIndex, ) from pandas.core.dtypes.missing import ( array_equivalent, isna, ) import pandas.core.algorithms as algos from pandas.core.array_algos.putmask import validate_putmask from pandas.core.arrays import Categorical from pandas.core.arrays.categorical import factorize_from_iterables import pandas.core.common as com import pandas.core.indexes.base as ibase from pandas.core.indexes.base import ( Index, _index_shared_docs, ensure_index, get_unanimous_names, ) from pandas.core.indexes.frozen import FrozenList from pandas.core.ops.invalid import make_invalid_op from pandas.core.sorting import ( get_group_index, indexer_from_factorized, lexsort_indexer, ) from pandas.io.formats.printing import pprint_thing if TYPE_CHECKING: from pandas import ( CategoricalIndex, DataFrame, Series, ) _index_doc_kwargs = dict(ibase._index_doc_kwargs) _index_doc_kwargs.update( {"klass": "MultiIndex", "target_klass": "MultiIndex or list of tuples"} ) class MultiIndexUIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.UInt64Engine): """ This class manages a MultiIndex by mapping label combinations to positive integers. """ _base = libindex.UInt64Engine def _codes_to_ints(self, codes): """ Transform combination(s) of uint64 in one uint64 (each), in a strictly monotonic way (i.e. respecting the lexicographic order of integer combinations): see BaseMultiIndexCodesEngine documentation. Parameters ---------- codes : 1- or 2-dimensional array of dtype uint64 Combinations of integers (one per row) Returns ------- scalar or 1-dimensional array, of dtype uint64 Integer(s) representing one combination (each). """ # Shift the representation of each level by the pre-calculated number # of bits: codes <<= self.offsets # Now sum and OR are in fact interchangeable. This is a simple # composition of the (disjunct) significant bits of each level (i.e. # each column in "codes") in a single positive integer: if codes.ndim == 1: # Single key return np.bitwise_or.reduce(codes) # Multiple keys return np.bitwise_or.reduce(codes, axis=1) class MultiIndexPyIntEngine(libindex.BaseMultiIndexCodesEngine, libindex.ObjectEngine): """ This class manages those (extreme) cases in which the number of possible label combinations overflows the 64 bits integers, and uses an ObjectEngine containing Python integers. """ _base = libindex.ObjectEngine def _codes_to_ints(self, codes): """ Transform combination(s) of uint64 in one Python integer (each), in a strictly monotonic way (i.e. respecting the lexicographic order of integer combinations): see BaseMultiIndexCodesEngine documentation. Parameters ---------- codes : 1- or 2-dimensional array of dtype uint64 Combinations of integers (one per row) Returns ------- int, or 1-dimensional array of dtype object Integer(s) representing one combination (each). """ # Shift the representation of each level by the pre-calculated number # of bits. Since this can overflow uint64, first make sure we are # working with Python integers: codes = codes.astype("object") << self.offsets # Now sum and OR are in fact interchangeable. This is a simple # composition of the (disjunct) significant bits of each level (i.e. # each column in "codes") in a single positive integer (per row): if codes.ndim == 1: # Single key return np.bitwise_or.reduce(codes) # Multiple keys return np.bitwise_or.reduce(codes, axis=1) def names_compat(meth: F) -> F: """ A decorator to allow either `name` or `names` keyword but not both. This makes it easier to share code with base class. """ @wraps(meth) def new_meth(self_or_cls, *args, **kwargs): if "name" in kwargs and "names" in kwargs: raise TypeError("Can only provide one of `names` and `name`") if "name" in kwargs: kwargs["names"] = kwargs.pop("name") return meth(self_or_cls, *args, **kwargs) return cast(F, new_meth) class MultiIndex(Index): """ A multi-level, or hierarchical, index object for pandas objects. Parameters ---------- levels : sequence of arrays The unique labels for each level. codes : sequence of arrays Integers for each level designating which label at each location. sortorder : optional int Level of sortedness (must be lexicographically sorted by that level). names : optional sequence of objects Names for each of the index levels. (name is accepted for compat). copy : bool, default False Copy the meta-data. verify_integrity : bool, default True Check that the levels/codes are consistent and valid. Attributes ---------- names levels codes nlevels levshape dtypes Methods ------- from_arrays from_tuples from_product from_frame set_levels set_codes to_frame to_flat_index sortlevel droplevel swaplevel reorder_levels remove_unused_levels get_level_values get_indexer get_loc get_locs get_loc_level drop See Also -------- MultiIndex.from_arrays : Convert list of arrays to MultiIndex. MultiIndex.from_product : Create a MultiIndex from the cartesian product of iterables. MultiIndex.from_tuples : Convert list of tuples to a MultiIndex. MultiIndex.from_frame : Make a MultiIndex from a DataFrame. Index : The base pandas Index type. Notes ----- See the `user guide `__ for more. Examples -------- A new ``MultiIndex`` is typically constructed using one of the helper methods :meth:`MultiIndex.from_arrays`, :meth:`MultiIndex.from_product` and :meth:`MultiIndex.from_tuples`. For example (using ``.from_arrays``): >>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']] >>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color')) MultiIndex([(1, 'red'), (1, 'blue'), (2, 'red'), (2, 'blue')], names=['number', 'color']) See further examples for how to construct a MultiIndex in the doc strings of the mentioned helper methods. """ _hidden_attrs = Index._hidden_attrs | frozenset() # initialize to zero-length tuples to make everything work _typ = "multiindex" _names: list[Hashable | None] = [] _levels = FrozenList() _codes = FrozenList() _comparables = ["names"] sortorder: int | None # -------------------------------------------------------------------- # Constructors def __new__( cls, levels=None, codes=None, sortorder=None, names=None, dtype=None, copy: bool = False, name=None, verify_integrity: bool = True, ) -> MultiIndex: # compat with Index if name is not None: names = name if levels is None or codes is None: raise TypeError("Must pass both levels and codes") if len(levels) != len(codes): raise ValueError("Length of levels and codes must be the same.") if len(levels) == 0: raise ValueError("Must pass non-zero number of levels/codes") result = object.__new__(cls) result._cache = {} # we've already validated levels and codes, so shortcut here result._set_levels(levels, copy=copy, validate=False) result._set_codes(codes, copy=copy, validate=False) result._names = [None] * len(levels) if names is not None: # handles name validation result._set_names(names) if sortorder is not None: result.sortorder = int(sortorder) else: result.sortorder = sortorder if verify_integrity: new_codes = result._verify_integrity() result._codes = new_codes result._reset_identity() result._references = None return result def _validate_codes(self, level: list, code: list): """ Reassign code values as -1 if their corresponding levels are NaN. Parameters ---------- code : list Code to reassign. level : list Level to check for missing values (NaN, NaT, None). Returns ------- new code where code value = -1 if it corresponds to a level with missing values (NaN, NaT, None). """ null_mask = isna(level) if np.any(null_mask): # error: Incompatible types in assignment # (expression has type "ndarray[Any, dtype[Any]]", # variable has type "List[Any]") code = np.where(null_mask[code], -1, code) # type: ignore[assignment] return code def _verify_integrity(self, codes: list | None = None, levels: list | None = None): """ Parameters ---------- codes : optional list Codes to check for validity. Defaults to current codes. levels : optional list Levels to check for validity. Defaults to current levels. Raises ------ ValueError If length of levels and codes don't match, if the codes for any level would exceed level bounds, or there are any duplicate levels. Returns ------- new codes where code value = -1 if it corresponds to a NaN level. """ # NOTE: Currently does not check, among other things, that cached # nlevels matches nor that sortorder matches actually sortorder. codes = codes or self.codes levels = levels or self.levels if len(levels) != len(codes): raise ValueError( "Length of levels and codes must match. NOTE: " "this index is in an inconsistent state." ) codes_length = len(codes[0]) for i, (level, level_codes) in enumerate(zip(levels, codes)): if len(level_codes) != codes_length: raise ValueError( f"Unequal code lengths: {[len(code_) for code_ in codes]}" ) if len(level_codes) and level_codes.max() >= len(level): raise ValueError( f"On level {i}, code max ({level_codes.max()}) >= length of " f"level ({len(level)}). NOTE: this index is in an " "inconsistent state" ) if len(level_codes) and level_codes.min() < -1: raise ValueError(f"On level {i}, code value ({level_codes.min()}) < -1") if not level.is_unique: raise ValueError( f"Level values must be unique: {list(level)} on level {i}" ) if self.sortorder is not None: if self.sortorder > _lexsort_depth(self.codes, self.nlevels): raise ValueError( "Value for sortorder must be inferior or equal to actual " f"lexsort_depth: sortorder {self.sortorder} " f"with lexsort_depth {_lexsort_depth(self.codes, self.nlevels)}" ) codes = [ self._validate_codes(level, code) for level, code in zip(levels, codes) ] new_codes = FrozenList(codes) return new_codes @classmethod def from_arrays( cls, arrays, sortorder=None, names: Sequence[Hashable] | Hashable | lib.NoDefault = lib.no_default, ) -> MultiIndex: """ Convert arrays to MultiIndex. Parameters ---------- arrays : list / sequence of array-likes Each array-like gives one level's value for each data point. len(arrays) is the number of levels. sortorder : int or None Level of sortedness (must be lexicographically sorted by that level). names : list / sequence of str, optional Names for the levels in the index. Returns ------- MultiIndex See Also -------- MultiIndex.from_tuples : Convert list of tuples to MultiIndex. MultiIndex.from_product : Make a MultiIndex from cartesian product of iterables. MultiIndex.from_frame : Make a MultiIndex from a DataFrame. Examples -------- >>> arrays = [[1, 1, 2, 2], ['red', 'blue', 'red', 'blue']] >>> pd.MultiIndex.from_arrays(arrays, names=('number', 'color')) MultiIndex([(1, 'red'), (1, 'blue'), (2, 'red'), (2, 'blue')], names=['number', 'color']) """ error_msg = "Input must be a list / sequence of array-likes." if not is_list_like(arrays): raise TypeError(error_msg) if is_iterator(arrays): arrays = list(arrays) # Check if elements of array are list-like for array in arrays: if not is_list_like(array): raise TypeError(error_msg) # Check if lengths of all arrays are equal or not, # raise ValueError, if not for i in range(1, len(arrays)): if len(arrays[i]) != len(arrays[i - 1]): raise ValueError("all arrays must be same length") codes, levels = factorize_from_iterables(arrays) if names is lib.no_default: names = [getattr(arr, "name", None) for arr in arrays] return cls( levels=levels, codes=codes, sortorder=sortorder, names=names, verify_integrity=False, ) @classmethod @names_compat def from_tuples( cls, tuples: Iterable[tuple[Hashable, ...]], sortorder: int | None = None, names: Sequence[Hashable] | Hashable = None, ) -> MultiIndex: """ Convert list of tuples to MultiIndex. Parameters ---------- tuples : list / sequence of tuple-likes Each tuple is the index of one row/column. sortorder : int or None Level of sortedness (must be lexicographically sorted by that level). names : list / sequence of str, optional Names for the levels in the index. Returns ------- MultiIndex See Also -------- MultiIndex.from_arrays : Convert list of arrays to MultiIndex. MultiIndex.from_product : Make a MultiIndex from cartesian product of iterables. MultiIndex.from_frame : Make a MultiIndex from a DataFrame. Examples -------- >>> tuples = [(1, 'red'), (1, 'blue'), ... (2, 'red'), (2, 'blue')] >>> pd.MultiIndex.from_tuples(tuples, names=('number', 'color')) MultiIndex([(1, 'red'), (1, 'blue'), (2, 'red'), (2, 'blue')], names=['number', 'color']) """ if not is_list_like(tuples): raise TypeError("Input must be a list / sequence of tuple-likes.") if is_iterator(tuples): tuples = list(tuples) tuples = cast(Collection[Tuple[Hashable, ...]], tuples) # handling the empty tuple cases if len(tuples) and all(isinstance(e, tuple) and not e for e in tuples): codes = [np.zeros(len(tuples))] levels = [Index(com.asarray_tuplesafe(tuples, dtype=np.dtype("object")))] return cls( levels=levels, codes=codes, sortorder=sortorder, names=names, verify_integrity=False, ) arrays: list[Sequence[Hashable]] if len(tuples) == 0: if names is None: raise TypeError("Cannot infer number of levels from empty list") # error: Argument 1 to "len" has incompatible type "Hashable"; # expected "Sized" arrays = [[]] * len(names) # type: ignore[arg-type] elif isinstance(tuples, (np.ndarray, Index)): if isinstance(tuples, Index): tuples = np.asarray(tuples._values) arrays = list(lib.tuples_to_object_array(tuples).T) elif isinstance(tuples, list): arrays = list(lib.to_object_array_tuples(tuples).T) else: arrs = zip(*tuples) arrays = cast(List[Sequence[Hashable]], arrs) return cls.from_arrays(arrays, sortorder=sortorder, names=names) @classmethod def from_product( cls, iterables: Sequence[Iterable[Hashable]], sortorder: int | None = None, names: Sequence[Hashable] | Hashable | lib.NoDefault = lib.no_default, ) -> MultiIndex: """ Make a MultiIndex from the cartesian product of multiple iterables. Parameters ---------- iterables : list / sequence of iterables Each iterable has unique labels for each level of the index. sortorder : int or None Level of sortedness (must be lexicographically sorted by that level). names : list / sequence of str, optional Names for the levels in the index. If not explicitly provided, names will be inferred from the elements of iterables if an element has a name attribute. Returns ------- MultiIndex See Also -------- MultiIndex.from_arrays : Convert list of arrays to MultiIndex. MultiIndex.from_tuples : Convert list of tuples to MultiIndex. MultiIndex.from_frame : Make a MultiIndex from a DataFrame. Examples -------- >>> numbers = [0, 1, 2] >>> colors = ['green', 'purple'] >>> pd.MultiIndex.from_product([numbers, colors], ... names=['number', 'color']) MultiIndex([(0, 'green'), (0, 'purple'), (1, 'green'), (1, 'purple'), (2, 'green'), (2, 'purple')], names=['number', 'color']) """ from pandas.core.reshape.util import cartesian_product if not is_list_like(iterables): raise TypeError("Input must be a list / sequence of iterables.") if is_iterator(iterables): iterables = list(iterables) codes, levels = factorize_from_iterables(iterables) if names is lib.no_default: names = [getattr(it, "name", None) for it in iterables] # codes are all ndarrays, so cartesian_product is lossless codes = cartesian_product(codes) return cls(levels, codes, sortorder=sortorder, names=names) @classmethod def from_frame(cls, df: DataFrame, sortorder=None, names=None) -> MultiIndex: """ Make a MultiIndex from a DataFrame. Parameters ---------- df : DataFrame DataFrame to be converted to MultiIndex. sortorder : int, optional Level of sortedness (must be lexicographically sorted by that level). names : list-like, optional If no names are provided, use the column names, or tuple of column names if the columns is a MultiIndex. If a sequence, overwrite names with the given sequence. Returns ------- MultiIndex The MultiIndex representation of the given DataFrame. See Also -------- MultiIndex.from_arrays : Convert list of arrays to MultiIndex. MultiIndex.from_tuples : Convert list of tuples to MultiIndex. MultiIndex.from_product : Make a MultiIndex from cartesian product of iterables. Examples -------- >>> df = pd.DataFrame([['HI', 'Temp'], ['HI', 'Precip'], ... ['NJ', 'Temp'], ['NJ', 'Precip']], ... columns=['a', 'b']) >>> df a b 0 HI Temp 1 HI Precip 2 NJ Temp 3 NJ Precip >>> pd.MultiIndex.from_frame(df) MultiIndex([('HI', 'Temp'), ('HI', 'Precip'), ('NJ', 'Temp'), ('NJ', 'Precip')], names=['a', 'b']) Using explicit names, instead of the column names >>> pd.MultiIndex.from_frame(df, names=['state', 'observation']) MultiIndex([('HI', 'Temp'), ('HI', 'Precip'), ('NJ', 'Temp'), ('NJ', 'Precip')], names=['state', 'observation']) """ if not isinstance(df, ABCDataFrame): raise TypeError("Input must be a DataFrame") column_names, columns = zip(*df.items()) names = column_names if names is None else names return cls.from_arrays(columns, sortorder=sortorder, names=names) # -------------------------------------------------------------------- @cache_readonly def _values(self) -> np.ndarray: # We override here, since our parent uses _data, which we don't use. values = [] for i in range(self.nlevels): index = self.levels[i] codes = self.codes[i] vals = index if is_categorical_dtype(vals.dtype): vals = cast("CategoricalIndex", vals) vals = vals._data._internal_get_values() if isinstance(vals.dtype, ExtensionDtype) or isinstance( vals, (ABCDatetimeIndex, ABCTimedeltaIndex) ): vals = vals.astype(object) vals = np.array(vals, copy=False) vals = algos.take_nd(vals, codes, fill_value=index._na_value) values.append(vals) arr = lib.fast_zip(values) return arr @property def values(self) -> np.ndarray: return self._values @property def array(self): """ Raises a ValueError for `MultiIndex` because there's no single array backing a MultiIndex. Raises ------ ValueError """ raise ValueError( "MultiIndex has no single backing array. Use " "'MultiIndex.to_numpy()' to get a NumPy array of tuples." ) @cache_readonly def dtypes(self) -> Series: """ Return the dtypes as a Series for the underlying MultiIndex. """ from pandas import Series names = com.fill_missing_names([level.name for level in self.levels]) return Series([level.dtype for level in self.levels], index=Index(names)) def __len__(self) -> int: return len(self.codes[0]) @property def size(self) -> int: """ Return the number of elements in the underlying data. """ # override Index.size to avoid materializing _values return len(self) # -------------------------------------------------------------------- # Levels Methods @cache_readonly def levels(self) -> FrozenList: # Use cache_readonly to ensure that self.get_locs doesn't repeatedly # create new IndexEngine # https://github.com/pandas-dev/pandas/issues/31648 result = [x._rename(name=name) for x, name in zip(self._levels, self._names)] for level in result: # disallow midx.levels[0].name = "foo" level._no_setting_name = True return FrozenList(result) def _set_levels( self, levels, *, level=None, copy: bool = False, validate: bool = True, verify_integrity: bool = False, ) -> None: # This is NOT part of the levels property because it should be # externally not allowed to set levels. User beware if you change # _levels directly if validate: if len(levels) == 0: raise ValueError("Must set non-zero number of levels.") if level is None and len(levels) != self.nlevels: raise ValueError("Length of levels must match number of levels.") if level is not None and len(levels) != len(level): raise ValueError("Length of levels must match length of level.") if level is None: new_levels = FrozenList( ensure_index(lev, copy=copy)._view() for lev in levels ) else: level_numbers = [self._get_level_number(lev) for lev in level] new_levels_list = list(self._levels) for lev_num, lev in zip(level_numbers, levels): new_levels_list[lev_num] = ensure_index(lev, copy=copy)._view() new_levels = FrozenList(new_levels_list) if verify_integrity: new_codes = self._verify_integrity(levels=new_levels) self._codes = new_codes names = self.names self._levels = new_levels if any(names): self._set_names(names) self._reset_cache() def set_levels( self, levels, *, level=None, verify_integrity: bool = True ) -> MultiIndex: """ Set new levels on MultiIndex. Defaults to returning new index. Parameters ---------- levels : sequence or list of sequence New level(s) to apply. level : int, level name, or sequence of int/level names (default None) Level(s) to set (None for all levels). verify_integrity : bool, default True If True, checks that levels and codes are compatible. Returns ------- MultiIndex Examples -------- >>> idx = pd.MultiIndex.from_tuples( ... [ ... (1, "one"), ... (1, "two"), ... (2, "one"), ... (2, "two"), ... (3, "one"), ... (3, "two") ... ], ... names=["foo", "bar"] ... ) >>> idx MultiIndex([(1, 'one'), (1, 'two'), (2, 'one'), (2, 'two'), (3, 'one'), (3, 'two')], names=['foo', 'bar']) >>> idx.set_levels([['a', 'b', 'c'], [1, 2]]) MultiIndex([('a', 1), ('a', 2), ('b', 1), ('b', 2), ('c', 1), ('c', 2)], names=['foo', 'bar']) >>> idx.set_levels(['a', 'b', 'c'], level=0) MultiIndex([('a', 'one'), ('a', 'two'), ('b', 'one'), ('b', 'two'), ('c', 'one'), ('c', 'two')], names=['foo', 'bar']) >>> idx.set_levels(['a', 'b'], level='bar') MultiIndex([(1, 'a'), (1, 'b'), (2, 'a'), (2, 'b'), (3, 'a'), (3, 'b')], names=['foo', 'bar']) If any of the levels passed to ``set_levels()`` exceeds the existing length, all of the values from that argument will be stored in the MultiIndex levels, though the values will be truncated in the MultiIndex output. >>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1]) MultiIndex([('a', 1), ('a', 2), ('b', 1), ('b', 2), ('c', 1), ('c', 2)], names=['foo', 'bar']) >>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1]).levels FrozenList([['a', 'b', 'c'], [1, 2, 3, 4]]) """ if is_list_like(levels) and not isinstance(levels, Index): levels = list(levels) level, levels = _require_listlike(level, levels, "Levels") idx = self._view() idx._reset_identity() idx._set_levels( levels, level=level, validate=True, verify_integrity=verify_integrity ) return idx @property def nlevels(self) -> int: """ Integer number of levels in this MultiIndex. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a'], ['b'], ['c']]) >>> mi MultiIndex([('a', 'b', 'c')], ) >>> mi.nlevels 3 """ return len(self._levels) @property def levshape(self) -> Shape: """ A tuple with the length of each level. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a'], ['b'], ['c']]) >>> mi MultiIndex([('a', 'b', 'c')], ) >>> mi.levshape (1, 1, 1) """ return tuple(len(x) for x in self.levels) # -------------------------------------------------------------------- # Codes Methods @property def codes(self): return self._codes def _set_codes( self, codes, *, level=None, copy: bool = False, validate: bool = True, verify_integrity: bool = False, ) -> None: if validate: if level is None and len(codes) != self.nlevels: raise ValueError("Length of codes must match number of levels") if level is not None and len(codes) != len(level): raise ValueError("Length of codes must match length of levels.") if level is None: new_codes = FrozenList( _coerce_indexer_frozen(level_codes, lev, copy=copy).view() for lev, level_codes in zip(self._levels, codes) ) else: level_numbers = [self._get_level_number(lev) for lev in level] new_codes_list = list(self._codes) for lev_num, level_codes in zip(level_numbers, codes): lev = self.levels[lev_num] new_codes_list[lev_num] = _coerce_indexer_frozen( level_codes, lev, copy=copy ) new_codes = FrozenList(new_codes_list) if verify_integrity: new_codes = self._verify_integrity(codes=new_codes) self._codes = new_codes self._reset_cache() def set_codes(self, codes, *, level=None, verify_integrity: bool = True): """ Set new codes on MultiIndex. Defaults to returning new index. Parameters ---------- codes : sequence or list of sequence New codes to apply. level : int, level name, or sequence of int/level names (default None) Level(s) to set (None for all levels). verify_integrity : bool, default True If True, checks that levels and codes are compatible. Returns ------- new index (of same type and class...etc) or None The same type as the caller or None if ``inplace=True``. Examples -------- >>> idx = pd.MultiIndex.from_tuples( ... [(1, "one"), (1, "two"), (2, "one"), (2, "two")], names=["foo", "bar"] ... ) >>> idx MultiIndex([(1, 'one'), (1, 'two'), (2, 'one'), (2, 'two')], names=['foo', 'bar']) >>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]]) MultiIndex([(2, 'one'), (1, 'one'), (2, 'two'), (1, 'two')], names=['foo', 'bar']) >>> idx.set_codes([1, 0, 1, 0], level=0) MultiIndex([(2, 'one'), (1, 'two'), (2, 'one'), (1, 'two')], names=['foo', 'bar']) >>> idx.set_codes([0, 0, 1, 1], level='bar') MultiIndex([(1, 'one'), (1, 'one'), (2, 'two'), (2, 'two')], names=['foo', 'bar']) >>> idx.set_codes([[1, 0, 1, 0], [0, 0, 1, 1]], level=[0, 1]) MultiIndex([(2, 'one'), (1, 'one'), (2, 'two'), (1, 'two')], names=['foo', 'bar']) """ level, codes = _require_listlike(level, codes, "Codes") idx = self._view() idx._reset_identity() idx._set_codes(codes, level=level, verify_integrity=verify_integrity) return idx # -------------------------------------------------------------------- # Index Internals @cache_readonly def _engine(self): # Calculate the number of bits needed to represent labels in each # level, as log2 of their sizes: # NaN values are shifted to 1 and missing values in other while # calculating the indexer are shifted to 0 sizes = np.ceil( np.log2( [ len(level) + libindex.multiindex_nulls_shift # type: ignore[attr-defined] for level in self.levels ] ) ) # Sum bit counts, starting from the _right_.... lev_bits = np.cumsum(sizes[::-1])[::-1] # ... in order to obtain offsets such that sorting the combination of # shifted codes (one for each level, resulting in a unique integer) is # equivalent to sorting lexicographically the codes themselves. Notice # that each level needs to be shifted by the number of bits needed to # represent the _previous_ ones: offsets = np.concatenate([lev_bits[1:], [0]]).astype("uint64") # Check the total number of bits needed for our representation: if lev_bits[0] > 64: # The levels would overflow a 64 bit uint - use Python integers: return MultiIndexPyIntEngine(self.levels, self.codes, offsets) return MultiIndexUIntEngine(self.levels, self.codes, offsets) # Return type "Callable[..., MultiIndex]" of "_constructor" incompatible with return # type "Type[MultiIndex]" in supertype "Index" @property def _constructor(self) -> Callable[..., MultiIndex]: # type: ignore[override] return type(self).from_tuples @doc(Index._shallow_copy) def _shallow_copy(self, values: np.ndarray, name=lib.no_default) -> MultiIndex: names = name if name is not lib.no_default else self.names return type(self).from_tuples(values, sortorder=None, names=names) def _view(self) -> MultiIndex: result = type(self)( levels=self.levels, codes=self.codes, sortorder=self.sortorder, names=self.names, verify_integrity=False, ) result._cache = self._cache.copy() result._cache.pop("levels", None) # GH32669 return result # -------------------------------------------------------------------- # error: Signature of "copy" incompatible with supertype "Index" def copy( # type: ignore[override] self, names=None, deep: bool = False, name=None, ): """ Make a copy of this object. Names, dtype, levels and codes can be passed and will be set on new copy. Parameters ---------- names : sequence, optional deep : bool, default False name : Label Kept for compatibility with 1-dimensional Index. Should not be used. Returns ------- MultiIndex Notes ----- In most cases, there should be no functional difference from using ``deep``, but if ``deep`` is passed it will attempt to deepcopy. This could be potentially expensive on large MultiIndex objects. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a'], ['b'], ['c']]) >>> mi MultiIndex([('a', 'b', 'c')], ) >>> mi.copy() MultiIndex([('a', 'b', 'c')], ) """ names = self._validate_names(name=name, names=names, deep=deep) keep_id = not deep levels, codes = None, None if deep: from copy import deepcopy levels = deepcopy(self.levels) codes = deepcopy(self.codes) levels = levels if levels is not None else self.levels codes = codes if codes is not None else self.codes new_index = type(self)( levels=levels, codes=codes, sortorder=self.sortorder, names=names, verify_integrity=False, ) new_index._cache = self._cache.copy() new_index._cache.pop("levels", None) # GH32669 if keep_id: new_index._id = self._id return new_index def __array__(self, dtype=None) -> np.ndarray: """the array interface, return my values""" return self.values def view(self, cls=None): """this is defined as a copy with the same identity""" result = self.copy() result._id = self._id return result @doc(Index.__contains__) def __contains__(self, key: Any) -> bool: hash(key) try: self.get_loc(key) return True except (LookupError, TypeError, ValueError): return False @cache_readonly def dtype(self) -> np.dtype: return np.dtype("O") def _is_memory_usage_qualified(self) -> bool: """return a boolean if we need a qualified .info display""" def f(level) -> bool: return "mixed" in level or "string" in level or "unicode" in level return any(f(level) for level in self._inferred_type_levels) # Cannot determine type of "memory_usage" @doc(Index.memory_usage) # type: ignore[has-type] def memory_usage(self, deep: bool = False) -> int: # we are overwriting our base class to avoid # computing .values here which could materialize # a tuple representation unnecessarily return self._nbytes(deep) @cache_readonly def nbytes(self) -> int: """return the number of bytes in the underlying data""" return self._nbytes(False) def _nbytes(self, deep: bool = False) -> int: """ return the number of bytes in the underlying data deeply introspect the level data if deep=True include the engine hashtable *this is in internal routine* """ # for implementations with no useful getsizeof (PyPy) objsize = 24 level_nbytes = sum(i.memory_usage(deep=deep) for i in self.levels) label_nbytes = sum(i.nbytes for i in self.codes) names_nbytes = sum(getsizeof(i, objsize) for i in self.names) result = level_nbytes + label_nbytes + names_nbytes # include our engine hashtable result += self._engine.sizeof(deep=deep) return result # -------------------------------------------------------------------- # Rendering Methods def _formatter_func(self, tup): """ Formats each item in tup according to its level's formatter function. """ formatter_funcs = [level._formatter_func for level in self.levels] return tuple(func(val) for func, val in zip(formatter_funcs, tup)) def _format_native_types( self, *, na_rep: str = "nan", **kwargs ) -> npt.NDArray[np.object_]: new_levels = [] new_codes = [] # go through the levels and format them for level, level_codes in zip(self.levels, self.codes): level_strs = level._format_native_types(na_rep=na_rep, **kwargs) # add nan values, if there are any mask = level_codes == -1 if mask.any(): nan_index = len(level_strs) # numpy 1.21 deprecated implicit string casting level_strs = level_strs.astype(str) level_strs = np.append(level_strs, na_rep) assert not level_codes.flags.writeable # i.e. copy is needed level_codes = level_codes.copy() # make writeable level_codes[mask] = nan_index new_levels.append(level_strs) new_codes.append(level_codes) if len(new_levels) == 1: # a single-level multi-index return Index(new_levels[0].take(new_codes[0]))._format_native_types() else: # reconstruct the multi-index mi = MultiIndex( levels=new_levels, codes=new_codes, names=self.names, sortorder=self.sortorder, verify_integrity=False, ) return mi._values def format( self, name: bool | None = None, formatter: Callable | None = None, na_rep: str | None = None, names: bool = False, space: int = 2, sparsify=None, adjoin: bool = True, ) -> list: if name is not None: names = name if len(self) == 0: return [] stringified_levels = [] for lev, level_codes in zip(self.levels, self.codes): na = na_rep if na_rep is not None else _get_na_rep(lev.dtype) if len(lev) > 0: formatted = lev.take(level_codes).format(formatter=formatter) # we have some NA mask = level_codes == -1 if mask.any(): formatted = np.array(formatted, dtype=object) formatted[mask] = na formatted = formatted.tolist() else: # weird all NA case formatted = [ pprint_thing(na if isna(x) else x, escape_chars=("\t", "\r", "\n")) for x in algos.take_nd(lev._values, level_codes) ] stringified_levels.append(formatted) result_levels = [] for lev, lev_name in zip(stringified_levels, self.names): level = [] if names: level.append( pprint_thing(lev_name, escape_chars=("\t", "\r", "\n")) if lev_name is not None else "" ) level.extend(np.array(lev, dtype=object)) result_levels.append(level) if sparsify is None: sparsify = get_option("display.multi_sparse") if sparsify: sentinel: Literal[""] | bool | lib.NoDefault = "" # GH3547 use value of sparsify as sentinel if it's "Falsey" assert isinstance(sparsify, bool) or sparsify is lib.no_default if sparsify in [False, lib.no_default]: sentinel = sparsify # little bit of a kludge job for #1217 result_levels = sparsify_labels( result_levels, start=int(names), sentinel=sentinel ) if adjoin: from pandas.io.formats.format import get_adjustment adj = get_adjustment() return adj.adjoin(space, *result_levels).split("\n") else: return result_levels # -------------------------------------------------------------------- # Names Methods def _get_names(self) -> FrozenList: return FrozenList(self._names) def _set_names(self, names, *, level=None, validate: bool = True): """ Set new names on index. Each name has to be a hashable type. Parameters ---------- values : str or sequence name(s) to set level : int, level name, or sequence of int/level names (default None) If the index is a MultiIndex (hierarchical), level(s) to set (None for all levels). Otherwise level must be None validate : bool, default True validate that the names match level lengths Raises ------ TypeError if each name is not hashable. Notes ----- sets names on levels. WARNING: mutates! Note that you generally want to set this *after* changing levels, so that it only acts on copies """ # GH 15110 # Don't allow a single string for names in a MultiIndex if names is not None and not is_list_like(names): raise ValueError("Names should be list-like for a MultiIndex") names = list(names) if validate: if level is not None and len(names) != len(level): raise ValueError("Length of names must match length of level.") if level is None and len(names) != self.nlevels: raise ValueError( "Length of names must match number of levels in MultiIndex." ) if level is None: level = range(self.nlevels) else: level = [self._get_level_number(lev) for lev in level] # set the name for lev, name in zip(level, names): if name is not None: # GH 20527 # All items in 'names' need to be hashable: if not is_hashable(name): raise TypeError( f"{type(self).__name__}.name must be a hashable type" ) self._names[lev] = name # If .levels has been accessed, the names in our cache will be stale. self._reset_cache() names = property( fset=_set_names, fget=_get_names, doc=""" Names of levels in MultiIndex. Examples -------- >>> mi = pd.MultiIndex.from_arrays( ... [[1, 2], [3, 4], [5, 6]], names=['x', 'y', 'z']) >>> mi MultiIndex([(1, 3, 5), (2, 4, 6)], names=['x', 'y', 'z']) >>> mi.names FrozenList(['x', 'y', 'z']) """, ) # -------------------------------------------------------------------- @cache_readonly def inferred_type(self) -> str: return "mixed" def _get_level_number(self, level) -> int: count = self.names.count(level) if (count > 1) and not is_integer(level): raise ValueError( f"The name {level} occurs multiple times, use a level number" ) try: level = self.names.index(level) except ValueError as err: if not is_integer(level): raise KeyError(f"Level {level} not found") from err if level < 0: level += self.nlevels if level < 0: orig_level = level - self.nlevels raise IndexError( f"Too many levels: Index has only {self.nlevels} levels, " f"{orig_level} is not a valid level number" ) from err # Note: levels are zero-based elif level >= self.nlevels: raise IndexError( f"Too many levels: Index has only {self.nlevels} levels, " f"not {level + 1}" ) from err return level @cache_readonly def is_monotonic_increasing(self) -> bool: """ Return a boolean if the values are equal or increasing. """ if any(-1 in code for code in self.codes): return False if all(level.is_monotonic_increasing for level in self.levels): # If each level is sorted, we can operate on the codes directly. GH27495 return libalgos.is_lexsorted( [x.astype("int64", copy=False) for x in self.codes] ) # reversed() because lexsort() wants the most significant key last. values = [ self._get_level_values(i)._values for i in reversed(range(len(self.levels))) ] try: # error: Argument 1 to "lexsort" has incompatible type # "List[Union[ExtensionArray, ndarray[Any, Any]]]"; # expected "Union[_SupportsArray[dtype[Any]], # _NestedSequence[_SupportsArray[dtype[Any]]], bool, # int, float, complex, str, bytes, _NestedSequence[Union # [bool, int, float, complex, str, bytes]]]" sort_order = np.lexsort(values) # type: ignore[arg-type] return Index(sort_order).is_monotonic_increasing except TypeError: # we have mixed types and np.lexsort is not happy return Index(self._values).is_monotonic_increasing @cache_readonly def is_monotonic_decreasing(self) -> bool: """ Return a boolean if the values are equal or decreasing. """ # monotonic decreasing if and only if reverse is monotonic increasing return self[::-1].is_monotonic_increasing @cache_readonly def _inferred_type_levels(self) -> list[str]: """return a list of the inferred types, one for each level""" return [i.inferred_type for i in self.levels] @doc(Index.duplicated) def duplicated(self, keep: DropKeep = "first") -> npt.NDArray[np.bool_]: shape = tuple(len(lev) for lev in self.levels) ids = get_group_index(self.codes, shape, sort=False, xnull=False) return duplicated(ids, keep) # error: Cannot override final attribute "_duplicated" # (previously declared in base class "IndexOpsMixin") _duplicated = duplicated # type: ignore[misc] def fillna(self, value=None, downcast=None): """ fillna is not implemented for MultiIndex """ raise NotImplementedError("isna is not defined for MultiIndex") @doc(Index.dropna) def dropna(self, how: AnyAll = "any") -> MultiIndex: nans = [level_codes == -1 for level_codes in self.codes] if how == "any": indexer = np.any(nans, axis=0) elif how == "all": indexer = np.all(nans, axis=0) else: raise ValueError(f"invalid how option: {how}") new_codes = [level_codes[~indexer] for level_codes in self.codes] return self.set_codes(codes=new_codes) def _get_level_values(self, level: int, unique: bool = False) -> Index: """ Return vector of label values for requested level, equal to the length of the index **this is an internal method** Parameters ---------- level : int unique : bool, default False if True, drop duplicated values Returns ------- Index """ lev = self.levels[level] level_codes = self.codes[level] name = self._names[level] if unique: level_codes = algos.unique(level_codes) filled = algos.take_nd(lev._values, level_codes, fill_value=lev._na_value) return lev._shallow_copy(filled, name=name) def get_level_values(self, level): """ Return vector of label values for requested level. Length of returned vector is equal to the length of the index. Parameters ---------- level : int or str ``level`` is either the integer position of the level in the MultiIndex, or the name of the level. Returns ------- Index Values is a level of this MultiIndex converted to a single :class:`Index` (or subclass thereof). Notes ----- If the level contains missing values, the result may be casted to ``float`` with missing values specified as ``NaN``. This is because the level is converted to a regular ``Index``. Examples -------- Create a MultiIndex: >>> mi = pd.MultiIndex.from_arrays((list('abc'), list('def'))) >>> mi.names = ['level_1', 'level_2'] Get level values by supplying level as either integer or name: >>> mi.get_level_values(0) Index(['a', 'b', 'c'], dtype='object', name='level_1') >>> mi.get_level_values('level_2') Index(['d', 'e', 'f'], dtype='object', name='level_2') If a level contains missing values, the return type of the level may be cast to ``float``. >>> pd.MultiIndex.from_arrays([[1, None, 2], [3, 4, 5]]).dtypes level_0 int64 level_1 int64 dtype: object >>> pd.MultiIndex.from_arrays([[1, None, 2], [3, 4, 5]]).get_level_values(0) Index([1.0, nan, 2.0], dtype='float64') """ level = self._get_level_number(level) values = self._get_level_values(level) return values @doc(Index.unique) def unique(self, level=None): if level is None: return self.drop_duplicates() else: level = self._get_level_number(level) return self._get_level_values(level=level, unique=True) def to_frame( self, index: bool = True, name=lib.no_default, allow_duplicates: bool = False, ) -> DataFrame: """ Create a DataFrame with the levels of the MultiIndex as columns. Column ordering is determined by the DataFrame constructor with data as a dict. Parameters ---------- index : bool, default True Set the index of the returned DataFrame as the original MultiIndex. name : list / sequence of str, optional The passed names should substitute index level names. allow_duplicates : bool, optional default False Allow duplicate column labels to be created. .. versionadded:: 1.5.0 Returns ------- DataFrame See Also -------- DataFrame : Two-dimensional, size-mutable, potentially heterogeneous tabular data. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a', 'b'], ['c', 'd']]) >>> mi MultiIndex([('a', 'c'), ('b', 'd')], ) >>> df = mi.to_frame() >>> df 0 1 a c a c b d b d >>> df = mi.to_frame(index=False) >>> df 0 1 0 a c 1 b d >>> df = mi.to_frame(name=['x', 'y']) >>> df x y a c a c b d b d """ from pandas import DataFrame if name is not lib.no_default: if not is_list_like(name): raise TypeError("'name' must be a list / sequence of column names.") if len(name) != len(self.levels): raise ValueError( "'name' should have same length as number of levels on index." ) idx_names = name else: idx_names = self._get_level_names() if not allow_duplicates and len(set(idx_names)) != len(idx_names): raise ValueError( "Cannot create duplicate column labels if allow_duplicates is False" ) # Guarantee resulting column order - PY36+ dict maintains insertion order result = DataFrame( {level: self._get_level_values(level) for level in range(len(self.levels))}, copy=False, ) result.columns = idx_names if index: result.index = self return result # error: Return type "Index" of "to_flat_index" incompatible with return type # "MultiIndex" in supertype "Index" def to_flat_index(self) -> Index: # type: ignore[override] """ Convert a MultiIndex to an Index of Tuples containing the level values. Returns ------- pd.Index Index with the MultiIndex data represented in Tuples. See Also -------- MultiIndex.from_tuples : Convert flat index back to MultiIndex. Notes ----- This method will simply return the caller if called by anything other than a MultiIndex. Examples -------- >>> index = pd.MultiIndex.from_product( ... [['foo', 'bar'], ['baz', 'qux']], ... names=['a', 'b']) >>> index.to_flat_index() Index([('foo', 'baz'), ('foo', 'qux'), ('bar', 'baz'), ('bar', 'qux')], dtype='object') """ return Index(self._values, tupleize_cols=False) def _is_lexsorted(self) -> bool: """ Return True if the codes are lexicographically sorted. Returns ------- bool Examples -------- In the below examples, the first level of the MultiIndex is sorted because a>> pd.MultiIndex.from_arrays([['a', 'b', 'c'], ... ['d', 'e', 'f']])._is_lexsorted() True >>> pd.MultiIndex.from_arrays([['a', 'b', 'c'], ... ['d', 'f', 'e']])._is_lexsorted() True In case there is a tie, the lexicographical sorting looks at the next level of the MultiIndex. >>> pd.MultiIndex.from_arrays([[0, 1, 1], ['a', 'b', 'c']])._is_lexsorted() True >>> pd.MultiIndex.from_arrays([[0, 1, 1], ['a', 'c', 'b']])._is_lexsorted() False >>> pd.MultiIndex.from_arrays([['a', 'a', 'b', 'b'], ... ['aa', 'bb', 'aa', 'bb']])._is_lexsorted() True >>> pd.MultiIndex.from_arrays([['a', 'a', 'b', 'b'], ... ['bb', 'aa', 'aa', 'bb']])._is_lexsorted() False """ return self._lexsort_depth == self.nlevels @cache_readonly def _lexsort_depth(self) -> int: """ Compute and return the lexsort_depth, the number of levels of the MultiIndex that are sorted lexically Returns ------- int """ if self.sortorder is not None: return self.sortorder return _lexsort_depth(self.codes, self.nlevels) def _sort_levels_monotonic(self, raise_if_incomparable: bool = False) -> MultiIndex: """ This is an *internal* function. Create a new MultiIndex from the current to monotonically sorted items IN the levels. This does not actually make the entire MultiIndex monotonic, JUST the levels. The resulting MultiIndex will have the same outward appearance, meaning the same .values and ordering. It will also be .equals() to the original. Returns ------- MultiIndex Examples -------- >>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']], ... codes=[[0, 0, 1, 1], [0, 1, 0, 1]]) >>> mi MultiIndex([('a', 'bb'), ('a', 'aa'), ('b', 'bb'), ('b', 'aa')], ) >>> mi.sort_values() MultiIndex([('a', 'aa'), ('a', 'bb'), ('b', 'aa'), ('b', 'bb')], ) """ if self._is_lexsorted() and self.is_monotonic_increasing: return self new_levels = [] new_codes = [] for lev, level_codes in zip(self.levels, self.codes): if not lev.is_monotonic_increasing: try: # indexer to reorder the levels indexer = lev.argsort() except TypeError: if raise_if_incomparable: raise else: lev = lev.take(indexer) # indexer to reorder the level codes indexer = ensure_platform_int(indexer) ri = lib.get_reverse_indexer(indexer, len(indexer)) level_codes = algos.take_nd(ri, level_codes) new_levels.append(lev) new_codes.append(level_codes) return MultiIndex( new_levels, new_codes, names=self.names, sortorder=self.sortorder, verify_integrity=False, ) def remove_unused_levels(self) -> MultiIndex: """ Create new MultiIndex from current that removes unused levels. Unused level(s) means levels that are not expressed in the labels. The resulting MultiIndex will have the same outward appearance, meaning the same .values and ordering. It will also be .equals() to the original. Returns ------- MultiIndex Examples -------- >>> mi = pd.MultiIndex.from_product([range(2), list('ab')]) >>> mi MultiIndex([(0, 'a'), (0, 'b'), (1, 'a'), (1, 'b')], ) >>> mi[2:] MultiIndex([(1, 'a'), (1, 'b')], ) The 0 from the first level is not represented and can be removed >>> mi2 = mi[2:].remove_unused_levels() >>> mi2.levels FrozenList([[1], ['a', 'b']]) """ new_levels = [] new_codes = [] changed = False for lev, level_codes in zip(self.levels, self.codes): # Since few levels are typically unused, bincount() is more # efficient than unique() - however it only accepts positive values # (and drops order): uniques = np.where(np.bincount(level_codes + 1) > 0)[0] - 1 has_na = int(len(uniques) and (uniques[0] == -1)) if len(uniques) != len(lev) + has_na: if lev.isna().any() and len(uniques) == len(lev): break # We have unused levels changed = True # Recalculate uniques, now preserving order. # Can easily be cythonized by exploiting the already existing # "uniques" and stop parsing "level_codes" when all items # are found: uniques = algos.unique(level_codes) if has_na: na_idx = np.where(uniques == -1)[0] # Just ensure that -1 is in first position: uniques[[0, na_idx[0]]] = uniques[[na_idx[0], 0]] # codes get mapped from uniques to 0:len(uniques) # -1 (if present) is mapped to last position code_mapping = np.zeros(len(lev) + has_na) # ... and reassigned value -1: code_mapping[uniques] = np.arange(len(uniques)) - has_na level_codes = code_mapping[level_codes] # new levels are simple lev = lev.take(uniques[has_na:]) new_levels.append(lev) new_codes.append(level_codes) result = self.view() if changed: result._reset_identity() result._set_levels(new_levels, validate=False) result._set_codes(new_codes, validate=False) return result # -------------------------------------------------------------------- # Pickling Methods def __reduce__(self): """Necessary for making this object picklable""" d = { "levels": list(self.levels), "codes": list(self.codes), "sortorder": self.sortorder, "names": list(self.names), } return ibase._new_Index, (type(self), d), None # -------------------------------------------------------------------- def __getitem__(self, key): if is_scalar(key): key = com.cast_scalar_indexer(key) retval = [] for lev, level_codes in zip(self.levels, self.codes): if level_codes[key] == -1: retval.append(np.nan) else: retval.append(lev[level_codes[key]]) return tuple(retval) else: # in general cannot be sure whether the result will be sorted sortorder = None if com.is_bool_indexer(key): key = np.asarray(key, dtype=bool) sortorder = self.sortorder elif isinstance(key, slice): if key.step is None or key.step > 0: sortorder = self.sortorder elif isinstance(key, Index): key = np.asarray(key) new_codes = [level_codes[key] for level_codes in self.codes] return MultiIndex( levels=self.levels, codes=new_codes, names=self.names, sortorder=sortorder, verify_integrity=False, ) def _getitem_slice(self: MultiIndex, slobj: slice) -> MultiIndex: """ Fastpath for __getitem__ when we know we have a slice. """ sortorder = None if slobj.step is None or slobj.step > 0: sortorder = self.sortorder new_codes = [level_codes[slobj] for level_codes in self.codes] return type(self)( levels=self.levels, codes=new_codes, names=self._names, sortorder=sortorder, verify_integrity=False, ) @Appender(_index_shared_docs["take"] % _index_doc_kwargs) def take( self: MultiIndex, indices, axis: Axis = 0, allow_fill: bool = True, fill_value=None, **kwargs, ) -> MultiIndex: nv.validate_take((), kwargs) indices = ensure_platform_int(indices) # only fill if we are passing a non-None fill_value allow_fill = self._maybe_disallow_fill(allow_fill, fill_value, indices) na_value = -1 taken = [lab.take(indices) for lab in self.codes] if allow_fill: mask = indices == -1 if mask.any(): masked = [] for new_label in taken: label_values = new_label label_values[mask] = na_value masked.append(np.asarray(label_values)) taken = masked return MultiIndex( levels=self.levels, codes=taken, names=self.names, verify_integrity=False ) def append(self, other): """ Append a collection of Index options together. Parameters ---------- other : Index or list/tuple of indices Returns ------- Index The combined index. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a'], ['b']]) >>> mi MultiIndex([('a', 'b')], ) >>> mi.append(mi) MultiIndex([('a', 'b'), ('a', 'b')], ) """ if not isinstance(other, (list, tuple)): other = [other] if all( (isinstance(o, MultiIndex) and o.nlevels >= self.nlevels) for o in other ): arrays, names = [], [] for i in range(self.nlevels): label = self._get_level_values(i) appended = [o._get_level_values(i) for o in other] arrays.append(label.append(appended)) single_label_name = all(label.name == x.name for x in appended) names.append(label.name if single_label_name else None) return MultiIndex.from_arrays(arrays, names=names) to_concat = (self._values,) + tuple(k._values for k in other) new_tuples = np.concatenate(to_concat) # if all(isinstance(x, MultiIndex) for x in other): try: # We only get here if other contains at least one index with tuples, # setting names to None automatically return MultiIndex.from_tuples(new_tuples) except (TypeError, IndexError): return Index(new_tuples) def argsort(self, *args, **kwargs) -> npt.NDArray[np.intp]: if len(args) == 0 and len(kwargs) == 0: # lexsort is significantly faster than self._values.argsort() target = self._sort_levels_monotonic(raise_if_incomparable=True) return lexsort_indexer(target._get_codes_for_sorting()) return self._values.argsort(*args, **kwargs) @Appender(_index_shared_docs["repeat"] % _index_doc_kwargs) def repeat(self, repeats: int, axis=None) -> MultiIndex: nv.validate_repeat((), {"axis": axis}) # error: Incompatible types in assignment (expression has type "ndarray", # variable has type "int") repeats = ensure_platform_int(repeats) # type: ignore[assignment] return MultiIndex( levels=self.levels, codes=[ level_codes.view(np.ndarray).astype(np.intp, copy=False).repeat(repeats) for level_codes in self.codes ], names=self.names, sortorder=self.sortorder, verify_integrity=False, ) # error: Signature of "drop" incompatible with supertype "Index" def drop( # type: ignore[override] self, codes, level: Index | np.ndarray | Iterable[Hashable] | None = None, errors: IgnoreRaise = "raise", ) -> MultiIndex: """ Make new MultiIndex with passed list of codes deleted. Parameters ---------- codes : array-like Must be a list of tuples when level is not specified. level : int or level name, default None errors : str, default 'raise' Returns ------- MultiIndex """ if level is not None: return self._drop_from_level(codes, level, errors) if not isinstance(codes, (np.ndarray, Index)): try: codes = com.index_labels_to_array(codes, dtype=np.dtype("object")) except ValueError: pass inds = [] for level_codes in codes: try: loc = self.get_loc(level_codes) # get_loc returns either an integer, a slice, or a boolean # mask if isinstance(loc, int): inds.append(loc) elif isinstance(loc, slice): step = loc.step if loc.step is not None else 1 inds.extend(range(loc.start, loc.stop, step)) elif com.is_bool_indexer(loc): if self._lexsort_depth == 0: warnings.warn( "dropping on a non-lexsorted multi-index " "without a level parameter may impact performance.", PerformanceWarning, stacklevel=find_stack_level(), ) loc = loc.nonzero()[0] inds.extend(loc) else: msg = f"unsupported indexer of type {type(loc)}" raise AssertionError(msg) except KeyError: if errors != "ignore": raise return self.delete(inds) def _drop_from_level( self, codes, level, errors: IgnoreRaise = "raise" ) -> MultiIndex: codes = com.index_labels_to_array(codes) i = self._get_level_number(level) index = self.levels[i] values = index.get_indexer(codes) # If nan should be dropped it will equal -1 here. We have to check which values # are not nan and equal -1, this means they are missing in the index nan_codes = isna(codes) values[(np.equal(nan_codes, False)) & (values == -1)] = -2 if index.shape[0] == self.shape[0]: values[np.equal(nan_codes, True)] = -2 not_found = codes[values == -2] if len(not_found) != 0 and errors != "ignore": raise KeyError(f"labels {not_found} not found in level") mask = ~algos.isin(self.codes[i], values) return self[mask] def swaplevel(self, i=-2, j=-1) -> MultiIndex: """ Swap level i with level j. Calling this method does not change the ordering of the values. Parameters ---------- i : int, str, default -2 First level of index to be swapped. Can pass level name as string. Type of parameters can be mixed. j : int, str, default -1 Second level of index to be swapped. Can pass level name as string. Type of parameters can be mixed. Returns ------- MultiIndex A new MultiIndex. See Also -------- Series.swaplevel : Swap levels i and j in a MultiIndex. DataFrame.swaplevel : Swap levels i and j in a MultiIndex on a particular axis. Examples -------- >>> mi = pd.MultiIndex(levels=[['a', 'b'], ['bb', 'aa']], ... codes=[[0, 0, 1, 1], [0, 1, 0, 1]]) >>> mi MultiIndex([('a', 'bb'), ('a', 'aa'), ('b', 'bb'), ('b', 'aa')], ) >>> mi.swaplevel(0, 1) MultiIndex([('bb', 'a'), ('aa', 'a'), ('bb', 'b'), ('aa', 'b')], ) """ new_levels = list(self.levels) new_codes = list(self.codes) new_names = list(self.names) i = self._get_level_number(i) j = self._get_level_number(j) new_levels[i], new_levels[j] = new_levels[j], new_levels[i] new_codes[i], new_codes[j] = new_codes[j], new_codes[i] new_names[i], new_names[j] = new_names[j], new_names[i] return MultiIndex( levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False ) def reorder_levels(self, order) -> MultiIndex: """ Rearrange levels using input order. May not drop or duplicate levels. Parameters ---------- order : list of int or list of str List representing new level order. Reference level by number (position) or by key (label). Returns ------- MultiIndex Examples -------- >>> mi = pd.MultiIndex.from_arrays([[1, 2], [3, 4]], names=['x', 'y']) >>> mi MultiIndex([(1, 3), (2, 4)], names=['x', 'y']) >>> mi.reorder_levels(order=[1, 0]) MultiIndex([(3, 1), (4, 2)], names=['y', 'x']) >>> mi.reorder_levels(order=['y', 'x']) MultiIndex([(3, 1), (4, 2)], names=['y', 'x']) """ order = [self._get_level_number(i) for i in order] if len(order) != self.nlevels: raise AssertionError( f"Length of order must be same as number of levels ({self.nlevels}), " f"got {len(order)}" ) new_levels = [self.levels[i] for i in order] new_codes = [self.codes[i] for i in order] new_names = [self.names[i] for i in order] return MultiIndex( levels=new_levels, codes=new_codes, names=new_names, verify_integrity=False ) def _get_codes_for_sorting(self) -> list[Categorical]: """ we are categorizing our codes by using the available categories (all, not just observed) excluding any missing ones (-1); this is in preparation for sorting, where we need to disambiguate that -1 is not a valid valid """ def cats(level_codes): return np.arange( np.array(level_codes).max() + 1 if len(level_codes) else 0, dtype=level_codes.dtype, ) return [ Categorical.from_codes(level_codes, cats(level_codes), ordered=True) for level_codes in self.codes ] def sortlevel( self, level: IndexLabel = 0, ascending: bool | list[bool] = True, sort_remaining: bool = True, ) -> tuple[MultiIndex, npt.NDArray[np.intp]]: """ Sort MultiIndex at the requested level. The result will respect the original ordering of the associated factor at that level. Parameters ---------- level : list-like, int or str, default 0 If a string is given, must be a name of the level. If list-like must be names or ints of levels. ascending : bool, default True False to sort in descending order. Can also be a list to specify a directed ordering. sort_remaining : sort by the remaining levels after level Returns ------- sorted_index : pd.MultiIndex Resulting index. indexer : np.ndarray[np.intp] Indices of output values in original index. Examples -------- >>> mi = pd.MultiIndex.from_arrays([[0, 0], [2, 1]]) >>> mi MultiIndex([(0, 2), (0, 1)], ) >>> mi.sortlevel() (MultiIndex([(0, 1), (0, 2)], ), array([1, 0])) >>> mi.sortlevel(sort_remaining=False) (MultiIndex([(0, 2), (0, 1)], ), array([0, 1])) >>> mi.sortlevel(1) (MultiIndex([(0, 1), (0, 2)], ), array([1, 0])) >>> mi.sortlevel(1, ascending=False) (MultiIndex([(0, 2), (0, 1)], ), array([0, 1])) """ if not is_list_like(level): level = [level] # error: Item "Hashable" of "Union[Hashable, Sequence[Hashable]]" has # no attribute "__iter__" (not iterable) level = [ self._get_level_number(lev) for lev in level # type: ignore[union-attr] ] sortorder = None # we have a directed ordering via ascending if isinstance(ascending, list): if not len(level) == len(ascending): raise ValueError("level must have same length as ascending") indexer = lexsort_indexer( [self.codes[lev] for lev in level], orders=ascending ) # level ordering else: codes = list(self.codes) shape = list(self.levshape) # partition codes and shape primary = tuple(codes[lev] for lev in level) primshp = tuple(shape[lev] for lev in level) # Reverse sorted to retain the order of # smaller indices that needs to be removed for lev in sorted(level, reverse=True): codes.pop(lev) shape.pop(lev) if sort_remaining: primary += primary + tuple(codes) primshp += primshp + tuple(shape) else: sortorder = level[0] indexer = indexer_from_factorized(primary, primshp, compress=False) if not ascending: indexer = indexer[::-1] indexer = ensure_platform_int(indexer) new_codes = [level_codes.take(indexer) for level_codes in self.codes] new_index = MultiIndex( codes=new_codes, levels=self.levels, names=self.names, sortorder=sortorder, verify_integrity=False, ) return new_index, indexer def _wrap_reindex_result(self, target, indexer, preserve_names: bool): if not isinstance(target, MultiIndex): if indexer is None: target = self elif (indexer >= 0).all(): target = self.take(indexer) else: try: target = MultiIndex.from_tuples(target) except TypeError: # not all tuples, see test_constructor_dict_multiindex_reindex_flat return target target = self._maybe_preserve_names(target, preserve_names) return target def _maybe_preserve_names(self, target: Index, preserve_names: bool) -> Index: if ( preserve_names and target.nlevels == self.nlevels and target.names != self.names ): target = target.copy(deep=False) target.names = self.names return target # -------------------------------------------------------------------- # Indexing Methods def _check_indexing_error(self, key) -> None: if not is_hashable(key) or is_iterator(key): # We allow tuples if they are hashable, whereas other Index # subclasses require scalar. # We have to explicitly exclude generators, as these are hashable. raise InvalidIndexError(key) @cache_readonly def _should_fallback_to_positional(self) -> bool: """ Should integer key(s) be treated as positional? """ # GH#33355 return self.levels[0]._should_fallback_to_positional def _get_indexer_strict( self, key, axis_name: str ) -> tuple[Index, npt.NDArray[np.intp]]: keyarr = key if not isinstance(keyarr, Index): keyarr = com.asarray_tuplesafe(keyarr) if len(keyarr) and not isinstance(keyarr[0], tuple): indexer = self._get_indexer_level_0(keyarr) self._raise_if_missing(key, indexer, axis_name) return self[indexer], indexer return super()._get_indexer_strict(key, axis_name) def _raise_if_missing(self, key, indexer, axis_name: str) -> None: keyarr = key if not isinstance(key, Index): keyarr = com.asarray_tuplesafe(key) if len(keyarr) and not isinstance(keyarr[0], tuple): # i.e. same condition for special case in MultiIndex._get_indexer_strict mask = indexer == -1 if mask.any(): check = self.levels[0].get_indexer(keyarr) cmask = check == -1 if cmask.any(): raise KeyError(f"{keyarr[cmask]} not in index") # We get here when levels still contain values which are not # actually in Index anymore raise KeyError(f"{keyarr} not in index") else: return super()._raise_if_missing(key, indexer, axis_name) def _get_indexer_level_0(self, target) -> npt.NDArray[np.intp]: """ Optimized equivalent to `self.get_level_values(0).get_indexer_for(target)`. """ lev = self.levels[0] codes = self._codes[0] cat = Categorical.from_codes(codes=codes, categories=lev) ci = Index(cat) return ci.get_indexer_for(target) def get_slice_bound( self, label: Hashable | Sequence[Hashable], side: Literal["left", "right"], ) -> int: """ For an ordered MultiIndex, compute slice bound that corresponds to given label. Returns leftmost (one-past-the-rightmost if `side=='right') position of given label. Parameters ---------- label : object or tuple of objects side : {'left', 'right'} Returns ------- int Index of label. Notes ----- This method only works if level 0 index of the MultiIndex is lexsorted. Examples -------- >>> mi = pd.MultiIndex.from_arrays([list('abbc'), list('gefd')]) Get the locations from the leftmost 'b' in the first level until the end of the multiindex: >>> mi.get_slice_bound('b', side="left") 1 Like above, but if you get the locations from the rightmost 'b' in the first level and 'f' in the second level: >>> mi.get_slice_bound(('b','f'), side="right") 3 See Also -------- MultiIndex.get_loc : Get location for a label or a tuple of labels. MultiIndex.get_locs : Get location for a label/slice/list/mask or a sequence of such. """ if not isinstance(label, tuple): label = (label,) return self._partial_tup_index(label, side=side) # pylint: disable-next=useless-parent-delegation def slice_locs(self, start=None, end=None, step=None) -> tuple[int, int]: """ For an ordered MultiIndex, compute the slice locations for input labels. The input labels can be tuples representing partial levels, e.g. for a MultiIndex with 3 levels, you can pass a single value (corresponding to the first level), or a 1-, 2-, or 3-tuple. Parameters ---------- start : label or tuple, default None If None, defaults to the beginning end : label or tuple If None, defaults to the end step : int or None Slice step Returns ------- (start, end) : (int, int) Notes ----- This method only works if the MultiIndex is properly lexsorted. So, if only the first 2 levels of a 3-level MultiIndex are lexsorted, you can only pass two levels to ``.slice_locs``. Examples -------- >>> mi = pd.MultiIndex.from_arrays([list('abbd'), list('deff')], ... names=['A', 'B']) Get the slice locations from the beginning of 'b' in the first level until the end of the multiindex: >>> mi.slice_locs(start='b') (1, 4) Like above, but stop at the end of 'b' in the first level and 'f' in the second level: >>> mi.slice_locs(start='b', end=('b', 'f')) (1, 3) See Also -------- MultiIndex.get_loc : Get location for a label or a tuple of labels. MultiIndex.get_locs : Get location for a label/slice/list/mask or a sequence of such. """ # This function adds nothing to its parent implementation (the magic # happens in get_slice_bound method), but it adds meaningful doc. return super().slice_locs(start, end, step) def _partial_tup_index(self, tup: tuple, side: Literal["left", "right"] = "left"): if len(tup) > self._lexsort_depth: raise UnsortedIndexError( f"Key length ({len(tup)}) was greater than MultiIndex lexsort depth " f"({self._lexsort_depth})" ) n = len(tup) start, end = 0, len(self) zipped = zip(tup, self.levels, self.codes) for k, (lab, lev, level_codes) in enumerate(zipped): section = level_codes[start:end] if lab not in lev and not isna(lab): # short circuit try: loc = algos.searchsorted(lev, lab, side=side) except TypeError as err: # non-comparable e.g. test_slice_locs_with_type_mismatch raise TypeError(f"Level type mismatch: {lab}") from err if not is_integer(loc): # non-comparable level, e.g. test_groupby_example raise TypeError(f"Level type mismatch: {lab}") if side == "right" and loc >= 0: loc -= 1 return start + algos.searchsorted(section, loc, side=side) idx = self._get_loc_single_level_index(lev, lab) if isinstance(idx, slice) and k < n - 1: # Get start and end value from slice, necessary when a non-integer # interval is given as input GH#37707 start = idx.start end = idx.stop elif k < n - 1: # error: Incompatible types in assignment (expression has type # "Union[ndarray[Any, dtype[signedinteger[Any]]] end = start + algos.searchsorted( # type: ignore[assignment] section, idx, side="right" ) # error: Incompatible types in assignment (expression has type # "Union[ndarray[Any, dtype[signedinteger[Any]]] start = start + algos.searchsorted( # type: ignore[assignment] section, idx, side="left" ) elif isinstance(idx, slice): idx = idx.start return start + algos.searchsorted(section, idx, side=side) else: return start + algos.searchsorted(section, idx, side=side) def _get_loc_single_level_index(self, level_index: Index, key: Hashable) -> int: """ If key is NA value, location of index unify as -1. Parameters ---------- level_index: Index key : label Returns ------- loc : int If key is NA value, loc is -1 Else, location of key in index. See Also -------- Index.get_loc : The get_loc method for (single-level) index. """ if is_scalar(key) and isna(key): # TODO: need is_valid_na_for_dtype(key, level_index.dtype) return -1 else: return level_index.get_loc(key) def get_loc(self, key): """ Get location for a label or a tuple of labels. The location is returned as an integer/slice or boolean mask. Parameters ---------- key : label or tuple of labels (one for each level) Returns ------- int, slice object or boolean mask If the key is past the lexsort depth, the return may be a boolean mask array, otherwise it is always a slice or int. See Also -------- Index.get_loc : The get_loc method for (single-level) index. MultiIndex.slice_locs : Get slice location given start label(s) and end label(s). MultiIndex.get_locs : Get location for a label/slice/list/mask or a sequence of such. Notes ----- The key cannot be a slice, list of same-level labels, a boolean mask, or a sequence of such. If you want to use those, use :meth:`MultiIndex.get_locs` instead. Examples -------- >>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')]) >>> mi.get_loc('b') slice(1, 3, None) >>> mi.get_loc(('b', 'e')) 1 """ self._check_indexing_error(key) def _maybe_to_slice(loc): """convert integer indexer to boolean mask or slice if possible""" if not isinstance(loc, np.ndarray) or loc.dtype != np.intp: return loc loc = lib.maybe_indices_to_slice(loc, len(self)) if isinstance(loc, slice): return loc mask = np.empty(len(self), dtype="bool") mask.fill(False) mask[loc] = True return mask if not isinstance(key, tuple): loc = self._get_level_indexer(key, level=0) return _maybe_to_slice(loc) keylen = len(key) if self.nlevels < keylen: raise KeyError( f"Key length ({keylen}) exceeds index depth ({self.nlevels})" ) if keylen == self.nlevels and self.is_unique: # TODO: what if we have an IntervalIndex level? # i.e. do we need _index_as_unique on that level? try: return self._engine.get_loc(key) except TypeError: # e.g. test_partial_slicing_with_multiindex partial string slicing loc, _ = self.get_loc_level(key, list(range(self.nlevels))) return loc # -- partial selection or non-unique index # break the key into 2 parts based on the lexsort_depth of the index; # the first part returns a continuous slice of the index; the 2nd part # needs linear search within the slice i = self._lexsort_depth lead_key, follow_key = key[:i], key[i:] if not lead_key: start = 0 stop = len(self) else: try: start, stop = self.slice_locs(lead_key, lead_key) except TypeError as err: # e.g. test_groupby_example key = ((0, 0, 1, 2), "new_col") # when self has 5 integer levels raise KeyError(key) from err if start == stop: raise KeyError(key) if not follow_key: return slice(start, stop) warnings.warn( "indexing past lexsort depth may impact performance.", PerformanceWarning, stacklevel=find_stack_level(), ) loc = np.arange(start, stop, dtype=np.intp) for i, k in enumerate(follow_key, len(lead_key)): mask = self.codes[i][loc] == self._get_loc_single_level_index( self.levels[i], k ) if not mask.all(): loc = loc[mask] if not len(loc): raise KeyError(key) return _maybe_to_slice(loc) if len(loc) != stop - start else slice(start, stop) def get_loc_level(self, key, level: IndexLabel = 0, drop_level: bool = True): """ Get location and sliced index for requested label(s)/level(s). Parameters ---------- key : label or sequence of labels level : int/level name or list thereof, optional drop_level : bool, default True If ``False``, the resulting index will not drop any level. Returns ------- tuple A 2-tuple where the elements : Element 0: int, slice object or boolean array. Element 1: The resulting sliced multiindex/index. If the key contains all levels, this will be ``None``. See Also -------- MultiIndex.get_loc : Get location for a label or a tuple of labels. MultiIndex.get_locs : Get location for a label/slice/list/mask or a sequence of such. Examples -------- >>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')], ... names=['A', 'B']) >>> mi.get_loc_level('b') (slice(1, 3, None), Index(['e', 'f'], dtype='object', name='B')) >>> mi.get_loc_level('e', level='B') (array([False, True, False]), Index(['b'], dtype='object', name='A')) >>> mi.get_loc_level(['b', 'e']) (1, None) """ if not isinstance(level, (list, tuple)): level = self._get_level_number(level) else: level = [self._get_level_number(lev) for lev in level] loc, mi = self._get_loc_level(key, level=level) if not drop_level: if lib.is_integer(loc): mi = self[loc : loc + 1] else: mi = self[loc] return loc, mi def _get_loc_level(self, key, level: int | list[int] = 0): """ get_loc_level but with `level` known to be positional, not name-based. """ # different name to distinguish from maybe_droplevels def maybe_mi_droplevels(indexer, levels): """ If level does not exist or all levels were dropped, the exception has to be handled outside. """ new_index = self[indexer] for i in sorted(levels, reverse=True): new_index = new_index._drop_level_numbers([i]) return new_index if isinstance(level, (tuple, list)): if len(key) != len(level): raise AssertionError( "Key for location must have same length as number of levels" ) result = None for lev, k in zip(level, key): loc, new_index = self._get_loc_level(k, level=lev) if isinstance(loc, slice): mask = np.zeros(len(self), dtype=bool) mask[loc] = True loc = mask result = loc if result is None else result & loc try: # FIXME: we should be only dropping levels on which we are # scalar-indexing mi = maybe_mi_droplevels(result, level) except ValueError: # droplevel failed because we tried to drop all levels, # i.e. len(level) == self.nlevels mi = self[result] return result, mi # kludge for #1796 if isinstance(key, list): key = tuple(key) if isinstance(key, tuple) and level == 0: try: # Check if this tuple is a single key in our first level if key in self.levels[0]: indexer = self._get_level_indexer(key, level=level) new_index = maybe_mi_droplevels(indexer, [0]) return indexer, new_index except (TypeError, InvalidIndexError): pass if not any(isinstance(k, slice) for k in key): if len(key) == self.nlevels and self.is_unique: # Complete key in unique index -> standard get_loc try: return (self._engine.get_loc(key), None) except KeyError as err: raise KeyError(key) from err except TypeError: # e.g. partial string indexing # test_partial_string_timestamp_multiindex pass # partial selection indexer = self.get_loc(key) ilevels = [i for i in range(len(key)) if key[i] != slice(None, None)] if len(ilevels) == self.nlevels: if is_integer(indexer): # we are dropping all levels return indexer, None # TODO: in some cases we still need to drop some levels, # e.g. test_multiindex_perf_warn # test_partial_string_timestamp_multiindex ilevels = [ i for i in range(len(key)) if ( not isinstance(key[i], str) or not self.levels[i]._supports_partial_string_indexing ) and key[i] != slice(None, None) ] if len(ilevels) == self.nlevels: # TODO: why? ilevels = [] return indexer, maybe_mi_droplevels(indexer, ilevels) else: indexer = None for i, k in enumerate(key): if not isinstance(k, slice): loc_level = self._get_level_indexer(k, level=i) if isinstance(loc_level, slice): if com.is_null_slice(loc_level) or com.is_full_slice( loc_level, len(self) ): # everything continue # e.g. test_xs_IndexSlice_argument_not_implemented k_index = np.zeros(len(self), dtype=bool) k_index[loc_level] = True else: k_index = loc_level elif com.is_null_slice(k): # taking everything, does not affect `indexer` below continue else: # FIXME: this message can be inaccurate, e.g. # test_series_varied_multiindex_alignment raise TypeError(f"Expected label or tuple of labels, got {key}") if indexer is None: indexer = k_index else: indexer &= k_index if indexer is None: indexer = slice(None, None) ilevels = [i for i in range(len(key)) if key[i] != slice(None, None)] return indexer, maybe_mi_droplevels(indexer, ilevels) else: indexer = self._get_level_indexer(key, level=level) if ( isinstance(key, str) and self.levels[level]._supports_partial_string_indexing ): # check to see if we did an exact lookup vs sliced check = self.levels[level].get_loc(key) if not is_integer(check): # e.g. test_partial_string_timestamp_multiindex return indexer, self[indexer] try: result_index = maybe_mi_droplevels(indexer, [level]) except ValueError: result_index = self[indexer] return indexer, result_index def _get_level_indexer( self, key, level: int = 0, indexer: npt.NDArray[np.bool_] | None = None ): # `level` kwarg is _always_ positional, never name # return a boolean array or slice showing where the key is # in the totality of values # if the indexer is provided, then use this level_index = self.levels[level] level_codes = self.codes[level] def convert_indexer(start, stop, step, indexer=indexer, codes=level_codes): # Compute a bool indexer to identify the positions to take. # If we have an existing indexer, we only need to examine the # subset of positions where the existing indexer is True. if indexer is not None: # we only need to look at the subset of codes where the # existing indexer equals True codes = codes[indexer] if step is None or step == 1: new_indexer = (codes >= start) & (codes < stop) else: r = np.arange(start, stop, step, dtype=codes.dtype) new_indexer = algos.isin(codes, r) if indexer is None: return new_indexer indexer = indexer.copy() indexer[indexer] = new_indexer return indexer if isinstance(key, slice): # handle a slice, returning a slice if we can # otherwise a boolean indexer step = key.step is_negative_step = step is not None and step < 0 try: if key.start is not None: start = level_index.get_loc(key.start) elif is_negative_step: start = len(level_index) - 1 else: start = 0 if key.stop is not None: stop = level_index.get_loc(key.stop) elif is_negative_step: stop = 0 elif isinstance(start, slice): stop = len(level_index) else: stop = len(level_index) - 1 except KeyError: # we have a partial slice (like looking up a partial date # string) start = stop = level_index.slice_indexer(key.start, key.stop, key.step) step = start.step if isinstance(start, slice) or isinstance(stop, slice): # we have a slice for start and/or stop # a partial date slicer on a DatetimeIndex generates a slice # note that the stop ALREADY includes the stopped point (if # it was a string sliced) start = getattr(start, "start", start) stop = getattr(stop, "stop", stop) return convert_indexer(start, stop, step) elif level > 0 or self._lexsort_depth == 0 or step is not None: # need to have like semantics here to right # searching as when we are using a slice # so adjust the stop by 1 (so we include stop) stop = (stop - 1) if is_negative_step else (stop + 1) return convert_indexer(start, stop, step) else: # sorted, so can return slice object -> view i = algos.searchsorted(level_codes, start, side="left") j = algos.searchsorted(level_codes, stop, side="right") return slice(i, j, step) else: idx = self._get_loc_single_level_index(level_index, key) if level > 0 or self._lexsort_depth == 0: # Desired level is not sorted if isinstance(idx, slice): # test_get_loc_partial_timestamp_multiindex locs = (level_codes >= idx.start) & (level_codes < idx.stop) return locs locs = np.array(level_codes == idx, dtype=bool, copy=False) if not locs.any(): # The label is present in self.levels[level] but unused: raise KeyError(key) return locs if isinstance(idx, slice): # e.g. test_partial_string_timestamp_multiindex start = algos.searchsorted(level_codes, idx.start, side="left") # NB: "left" here bc of slice semantics end = algos.searchsorted(level_codes, idx.stop, side="left") else: start = algos.searchsorted(level_codes, idx, side="left") end = algos.searchsorted(level_codes, idx, side="right") if start == end: # The label is present in self.levels[level] but unused: raise KeyError(key) return slice(start, end) def get_locs(self, seq): """ Get location for a sequence of labels. Parameters ---------- seq : label, slice, list, mask or a sequence of such You should use one of the above for each level. If a level should not be used, set it to ``slice(None)``. Returns ------- numpy.ndarray NumPy array of integers suitable for passing to iloc. See Also -------- MultiIndex.get_loc : Get location for a label or a tuple of labels. MultiIndex.slice_locs : Get slice location given start label(s) and end label(s). Examples -------- >>> mi = pd.MultiIndex.from_arrays([list('abb'), list('def')]) >>> mi.get_locs('b') # doctest: +SKIP array([1, 2], dtype=int64) >>> mi.get_locs([slice(None), ['e', 'f']]) # doctest: +SKIP array([1, 2], dtype=int64) >>> mi.get_locs([[True, False, True], slice('e', 'f')]) # doctest: +SKIP array([2], dtype=int64) """ # must be lexsorted to at least as many levels true_slices = [i for (i, s) in enumerate(com.is_true_slices(seq)) if s] if true_slices and true_slices[-1] >= self._lexsort_depth: raise UnsortedIndexError( "MultiIndex slicing requires the index to be lexsorted: slicing " f"on levels {true_slices}, lexsort depth {self._lexsort_depth}" ) if any(x is Ellipsis for x in seq): raise NotImplementedError( "MultiIndex does not support indexing with Ellipsis" ) n = len(self) def _to_bool_indexer(indexer) -> npt.NDArray[np.bool_]: if isinstance(indexer, slice): new_indexer = np.zeros(n, dtype=np.bool_) new_indexer[indexer] = True return new_indexer return indexer # a bool indexer for the positions we want to take indexer: npt.NDArray[np.bool_] | None = None for i, k in enumerate(seq): lvl_indexer: npt.NDArray[np.bool_] | slice | None = None if com.is_bool_indexer(k): if len(k) != n: raise ValueError( "cannot index with a boolean indexer that " "is not the same length as the index" ) lvl_indexer = np.asarray(k) elif is_list_like(k): # a collection of labels to include from this level (these are or'd) # GH#27591 check if this is a single tuple key in the level try: lvl_indexer = self._get_level_indexer(k, level=i, indexer=indexer) except (InvalidIndexError, TypeError, KeyError) as err: # InvalidIndexError e.g. non-hashable, fall back to treating # this as a sequence of labels # KeyError it can be ambiguous if this is a label or sequence # of labels # github.com/pandas-dev/pandas/issues/39424#issuecomment-871626708 for x in k: if not is_hashable(x): # e.g. slice raise err # GH 39424: Ignore not founds # GH 42351: No longer ignore not founds & enforced in 2.0 # TODO: how to handle IntervalIndex level? (no test cases) item_indexer = self._get_level_indexer( x, level=i, indexer=indexer ) if lvl_indexer is None: lvl_indexer = _to_bool_indexer(item_indexer) elif isinstance(item_indexer, slice): lvl_indexer[item_indexer] = True # type: ignore[index] else: lvl_indexer |= item_indexer if lvl_indexer is None: # no matches we are done # test_loc_getitem_duplicates_multiindex_empty_indexer return np.array([], dtype=np.intp) elif com.is_null_slice(k): # empty slice if indexer is None and i == len(seq) - 1: return np.arange(n, dtype=np.intp) continue else: # a slice or a single label lvl_indexer = self._get_level_indexer(k, level=i, indexer=indexer) # update indexer lvl_indexer = _to_bool_indexer(lvl_indexer) if indexer is None: indexer = lvl_indexer else: indexer &= lvl_indexer if not np.any(indexer) and np.any(lvl_indexer): raise KeyError(seq) # empty indexer if indexer is None: return np.array([], dtype=np.intp) pos_indexer = indexer.nonzero()[0] return self._reorder_indexer(seq, pos_indexer) # -------------------------------------------------------------------- def _reorder_indexer( self, seq: tuple[Scalar | Iterable | AnyArrayLike, ...], indexer: npt.NDArray[np.intp], ) -> npt.NDArray[np.intp]: """ Reorder an indexer of a MultiIndex (self) so that the labels are in the same order as given in seq Parameters ---------- seq : label/slice/list/mask or a sequence of such indexer: a position indexer of self Returns ------- indexer : a sorted position indexer of self ordered as seq """ # check if sorting is necessary need_sort = False for i, k in enumerate(seq): if com.is_null_slice(k) or com.is_bool_indexer(k) or is_scalar(k): pass elif is_list_like(k): if len(k) <= 1: # type: ignore[arg-type] pass elif self._is_lexsorted(): # If the index is lexsorted and the list_like label # in seq are sorted then we do not need to sort k_codes = self.levels[i].get_indexer(k) k_codes = k_codes[k_codes >= 0] # Filter absent keys # True if the given codes are not ordered need_sort = (k_codes[:-1] > k_codes[1:]).any() else: need_sort = True elif isinstance(k, slice): if self._is_lexsorted(): need_sort = k.step is not None and k.step < 0 else: need_sort = True else: need_sort = True if need_sort: break if not need_sort: return indexer n = len(self) keys: tuple[np.ndarray, ...] = () # For each level of the sequence in seq, map the level codes with the # order they appears in a list-like sequence # This mapping is then use to reorder the indexer for i, k in enumerate(seq): if is_scalar(k): # GH#34603 we want to treat a scalar the same as an all equal list k = [k] if com.is_bool_indexer(k): new_order = np.arange(n)[indexer] elif is_list_like(k): # Generate a map with all level codes as sorted initially k = algos.unique(k) key_order_map = np.ones(len(self.levels[i]), dtype=np.uint64) * len( self.levels[i] ) # Set order as given in the indexer list level_indexer = self.levels[i].get_indexer(k) level_indexer = level_indexer[level_indexer >= 0] # Filter absent keys key_order_map[level_indexer] = np.arange(len(level_indexer)) new_order = key_order_map[self.codes[i][indexer]] elif isinstance(k, slice) and k.step is not None and k.step < 0: # flip order for negative step new_order = np.arange(n)[::-1][indexer] elif isinstance(k, slice) and k.start is None and k.stop is None: # slice(None) should not determine order GH#31330 new_order = np.ones((n,), dtype=np.intp)[indexer] else: # For all other case, use the same order as the level new_order = np.arange(n)[indexer] keys = (new_order,) + keys # Find the reordering using lexsort on the keys mapping ind = np.lexsort(keys) return indexer[ind] def truncate(self, before=None, after=None) -> MultiIndex: """ Slice index between two labels / tuples, return new MultiIndex. Parameters ---------- before : label or tuple, can be partial. Default None None defaults to start. after : label or tuple, can be partial. Default None None defaults to end. Returns ------- MultiIndex The truncated MultiIndex. Examples -------- >>> mi = pd.MultiIndex.from_arrays([['a', 'b', 'c'], ['x', 'y', 'z']]) >>> mi MultiIndex([('a', 'x'), ('b', 'y'), ('c', 'z')], ) >>> mi.truncate(before='a', after='b') MultiIndex([('a', 'x'), ('b', 'y')], ) """ if after and before and after < before: raise ValueError("after < before") i, j = self.levels[0].slice_locs(before, after) left, right = self.slice_locs(before, after) new_levels = list(self.levels) new_levels[0] = new_levels[0][i:j] new_codes = [level_codes[left:right] for level_codes in self.codes] new_codes[0] = new_codes[0] - i return MultiIndex( levels=new_levels, codes=new_codes, names=self._names, verify_integrity=False, ) def equals(self, other: object) -> bool: """ Determines if two MultiIndex objects have the same labeling information (the levels themselves do not necessarily have to be the same) See Also -------- equal_levels """ if self.is_(other): return True if not isinstance(other, Index): return False if len(self) != len(other): return False if not isinstance(other, MultiIndex): # d-level MultiIndex can equal d-tuple Index if not self._should_compare(other): # object Index or Categorical[object] may contain tuples return False return array_equivalent(self._values, other._values) if self.nlevels != other.nlevels: return False for i in range(self.nlevels): self_codes = self.codes[i] other_codes = other.codes[i] self_mask = self_codes == -1 other_mask = other_codes == -1 if not np.array_equal(self_mask, other_mask): return False self_codes = self_codes[~self_mask] self_values = self.levels[i]._values.take(self_codes) other_codes = other_codes[~other_mask] other_values = other.levels[i]._values.take(other_codes) # since we use NaT both datetime64 and timedelta64 we can have a # situation where a level is typed say timedelta64 in self (IOW it # has other values than NaT) but types datetime64 in other (where # its all NaT) but these are equivalent if len(self_values) == 0 and len(other_values) == 0: continue if not isinstance(self_values, np.ndarray): # i.e. ExtensionArray if not self_values.equals(other_values): return False elif not isinstance(other_values, np.ndarray): # i.e. other is ExtensionArray if not other_values.equals(self_values): return False else: if not array_equivalent(self_values, other_values): return False return True def equal_levels(self, other: MultiIndex) -> bool: """ Return True if the levels of both MultiIndex objects are the same """ if self.nlevels != other.nlevels: return False for i in range(self.nlevels): if not self.levels[i].equals(other.levels[i]): return False return True # -------------------------------------------------------------------- # Set Methods def _union(self, other, sort) -> MultiIndex: other, result_names = self._convert_can_do_setop(other) if other.has_duplicates: # This is only necessary if other has dupes, # otherwise difference is faster result = super()._union(other, sort) if isinstance(result, MultiIndex): return result return MultiIndex.from_arrays( zip(*result), sortorder=None, names=result_names ) else: right_missing = other.difference(self, sort=False) if len(right_missing): result = self.append(right_missing) else: result = self._get_reconciled_name_object(other) if sort is not False: try: result = result.sort_values() except TypeError: if sort is True: raise warnings.warn( "The values in the array are unorderable. " "Pass `sort=False` to suppress this warning.", RuntimeWarning, stacklevel=find_stack_level(), ) return result def _is_comparable_dtype(self, dtype: DtypeObj) -> bool: return is_object_dtype(dtype) def _get_reconciled_name_object(self, other) -> MultiIndex: """ If the result of a set operation will be self, return self, unless the names change, in which case make a shallow copy of self. """ names = self._maybe_match_names(other) if self.names != names: # error: Cannot determine type of "rename" return self.rename(names) # type: ignore[has-type] return self def _maybe_match_names(self, other): """ Try to find common names to attach to the result of an operation between a and b. Return a consensus list of names if they match at least partly or list of None if they have completely different names. """ if len(self.names) != len(other.names): return [None] * len(self.names) names = [] for a_name, b_name in zip(self.names, other.names): if a_name == b_name: names.append(a_name) else: # TODO: what if they both have np.nan for their names? names.append(None) return names def _wrap_intersection_result(self, other, result) -> MultiIndex: _, result_names = self._convert_can_do_setop(other) return result.set_names(result_names) def _wrap_difference_result(self, other, result: MultiIndex) -> MultiIndex: _, result_names = self._convert_can_do_setop(other) if len(result) == 0: return result.remove_unused_levels().set_names(result_names) else: return result.set_names(result_names) def _convert_can_do_setop(self, other): result_names = self.names if not isinstance(other, Index): if len(other) == 0: return self[:0], self.names else: msg = "other must be a MultiIndex or a list of tuples" try: other = MultiIndex.from_tuples(other, names=self.names) except (ValueError, TypeError) as err: # ValueError raised by tuples_to_object_array if we # have non-object dtype raise TypeError(msg) from err else: result_names = get_unanimous_names(self, other) return other, result_names # -------------------------------------------------------------------- @doc(Index.astype) def astype(self, dtype, copy: bool = True): dtype = pandas_dtype(dtype) if is_categorical_dtype(dtype): msg = "> 1 ndim Categorical are not supported at this time" raise NotImplementedError(msg) if not is_object_dtype(dtype): raise TypeError( "Setting a MultiIndex dtype to anything other than object " "is not supported" ) if copy is True: return self._view() return self def _validate_fill_value(self, item): if isinstance(item, MultiIndex): # GH#43212 if item.nlevels != self.nlevels: raise ValueError("Item must have length equal to number of levels.") return item._values elif not isinstance(item, tuple): # Pad the key with empty strings if lower levels of the key # aren't specified: item = (item,) + ("",) * (self.nlevels - 1) elif len(item) != self.nlevels: raise ValueError("Item must have length equal to number of levels.") return item def putmask(self, mask, value: MultiIndex) -> MultiIndex: """ Return a new MultiIndex of the values set with the mask. Parameters ---------- mask : array like value : MultiIndex Must either be the same length as self or length one Returns ------- MultiIndex """ mask, noop = validate_putmask(self, mask) if noop: return self.copy() if len(mask) == len(value): subset = value[mask].remove_unused_levels() else: subset = value.remove_unused_levels() new_levels = [] new_codes = [] for i, (value_level, level, level_codes) in enumerate( zip(subset.levels, self.levels, self.codes) ): new_level = level.union(value_level, sort=False) value_codes = new_level.get_indexer_for(subset.get_level_values(i)) new_code = ensure_int64(level_codes) new_code[mask] = value_codes new_levels.append(new_level) new_codes.append(new_code) return MultiIndex( levels=new_levels, codes=new_codes, names=self.names, verify_integrity=False ) def insert(self, loc: int, item) -> MultiIndex: """ Make new MultiIndex inserting new item at location Parameters ---------- loc : int item : tuple Must be same length as number of levels in the MultiIndex Returns ------- new_index : Index """ item = self._validate_fill_value(item) new_levels = [] new_codes = [] for k, level, level_codes in zip(item, self.levels, self.codes): if k not in level: # have to insert into level # must insert at end otherwise you have to recompute all the # other codes lev_loc = len(level) level = level.insert(lev_loc, k) else: lev_loc = level.get_loc(k) new_levels.append(level) new_codes.append(np.insert(ensure_int64(level_codes), loc, lev_loc)) return MultiIndex( levels=new_levels, codes=new_codes, names=self.names, verify_integrity=False ) def delete(self, loc) -> MultiIndex: """ Make new index with passed location deleted Returns ------- new_index : MultiIndex """ new_codes = [np.delete(level_codes, loc) for level_codes in self.codes] return MultiIndex( levels=self.levels, codes=new_codes, names=self.names, verify_integrity=False, ) @doc(Index.isin) def isin(self, values, level=None) -> npt.NDArray[np.bool_]: if isinstance(values, Generator): values = list(values) if level is None: if len(values) == 0: return np.zeros((len(self),), dtype=np.bool_) if not isinstance(values, MultiIndex): values = MultiIndex.from_tuples(values) return values.unique().get_indexer_for(self) != -1 else: num = self._get_level_number(level) levs = self.get_level_values(num) if levs.size == 0: return np.zeros(len(levs), dtype=np.bool_) return levs.isin(values) # error: Incompatible types in assignment (expression has type overloaded function, # base class "Index" defined the type as "Callable[[Index, Any, bool], Any]") rename = Index.set_names # type: ignore[assignment] # --------------------------------------------------------------- # Arithmetic/Numeric Methods - Disabled __add__ = make_invalid_op("__add__") __radd__ = make_invalid_op("__radd__") __iadd__ = make_invalid_op("__iadd__") __sub__ = make_invalid_op("__sub__") __rsub__ = make_invalid_op("__rsub__") __isub__ = make_invalid_op("__isub__") __pow__ = make_invalid_op("__pow__") __rpow__ = make_invalid_op("__rpow__") __mul__ = make_invalid_op("__mul__") __rmul__ = make_invalid_op("__rmul__") __floordiv__ = make_invalid_op("__floordiv__") __rfloordiv__ = make_invalid_op("__rfloordiv__") __truediv__ = make_invalid_op("__truediv__") __rtruediv__ = make_invalid_op("__rtruediv__") __mod__ = make_invalid_op("__mod__") __rmod__ = make_invalid_op("__rmod__") __divmod__ = make_invalid_op("__divmod__") __rdivmod__ = make_invalid_op("__rdivmod__") # Unary methods disabled __neg__ = make_invalid_op("__neg__") __pos__ = make_invalid_op("__pos__") __abs__ = make_invalid_op("__abs__") __invert__ = make_invalid_op("__invert__") def _lexsort_depth(codes: list[np.ndarray], nlevels: int) -> int: """Count depth (up to a maximum of `nlevels`) with which codes are lexsorted.""" int64_codes = [ensure_int64(level_codes) for level_codes in codes] for k in range(nlevels, 0, -1): if libalgos.is_lexsorted(int64_codes[:k]): return k return 0 def sparsify_labels(label_list, start: int = 0, sentinel: object = ""): pivoted = list(zip(*label_list)) k = len(label_list) result = pivoted[: start + 1] prev = pivoted[start] for cur in pivoted[start + 1 :]: sparse_cur = [] for i, (p, t) in enumerate(zip(prev, cur)): if i == k - 1: sparse_cur.append(t) result.append(sparse_cur) break if p == t: sparse_cur.append(sentinel) else: sparse_cur.extend(cur[i:]) result.append(sparse_cur) break prev = cur return list(zip(*result)) def _get_na_rep(dtype) -> str: if is_extension_array_dtype(dtype): return f"{dtype.na_value}" else: dtype = dtype.type return {np.datetime64: "NaT", np.timedelta64: "NaT"}.get(dtype, "NaN") def maybe_droplevels(index: Index, key) -> Index: """ Attempt to drop level or levels from the given index. Parameters ---------- index: Index key : scalar or tuple Returns ------- Index """ # drop levels original_index = index if isinstance(key, tuple): # Caller is responsible for ensuring the key is not an entry in the first # level of the MultiIndex. for _ in key: try: index = index._drop_level_numbers([0]) except ValueError: # we have dropped too much, so back out return original_index else: try: index = index._drop_level_numbers([0]) except ValueError: pass return index def _coerce_indexer_frozen(array_like, categories, copy: bool = False) -> np.ndarray: """ Coerce the array-like indexer to the smallest integer dtype that can encode all of the given categories. Parameters ---------- array_like : array-like categories : array-like copy : bool Returns ------- np.ndarray Non-writeable. """ array_like = coerce_indexer_dtype(array_like, categories) if copy: array_like = array_like.copy() array_like.flags.writeable = False return array_like def _require_listlike(level, arr, arrname: str): """ Ensure that level is either None or listlike, and arr is list-of-listlike. """ if level is not None and not is_list_like(level): if not is_list_like(arr): raise TypeError(f"{arrname} must be list-like") if len(arr) > 0 and is_list_like(arr[0]): raise TypeError(f"{arrname} must be list-like") level = [level] arr = [arr] elif level is None or is_list_like(level): if not is_list_like(arr) or not is_list_like(arr[0]): raise TypeError(f"{arrname} must be list of lists-like") return level, arr