""" frozen (immutable) data structures to support MultiIndexing These are used for: - .names (FrozenList) """ from typing import Any from pandas.core.base import PandasObject from pandas.io.formats.printing import pprint_thing class FrozenList(PandasObject, list): """ Container that doesn't allow setting item *but* because it's technically non-hashable, will be used for lookups, appropriately, etc. """ # Side note: This has to be of type list. Otherwise, # it messes up PyTables type checks. def union(self, other) -> "FrozenList": """ Returns a FrozenList with other concatenated to the end of self. Parameters ---------- other : array-like The array-like whose elements we are concatenating. Returns ------- FrozenList The collection difference between self and other. """ if isinstance(other, tuple): other = list(other) return type(self)(super().__add__(other)) def difference(self, other) -> "FrozenList": """ Returns a FrozenList with elements from other removed from self. Parameters ---------- other : array-like The array-like whose elements we are removing self. Returns ------- FrozenList The collection difference between self and other. """ other = set(other) temp = [x for x in self if x not in other] return type(self)(temp) # TODO: Consider deprecating these in favor of `union` (xref gh-15506) __add__ = __iadd__ = union def __getitem__(self, n): if isinstance(n, slice): return type(self)(super().__getitem__(n)) return super().__getitem__(n) def __radd__(self, other): if isinstance(other, tuple): other = list(other) return type(self)(other + list(self)) def __eq__(self, other: Any) -> bool: if isinstance(other, (tuple, FrozenList)): other = list(other) return super().__eq__(other) __req__ = __eq__ def __mul__(self, other): return type(self)(super().__mul__(other)) __imul__ = __mul__ def __reduce__(self): return type(self), (list(self),) def __hash__(self): return hash(tuple(self)) def _disabled(self, *args, **kwargs): """ This method will not function because object is immutable. """ raise TypeError(f"'{type(self).__name__}' does not support mutable operations.") def __str__(self) -> str: return pprint_thing(self, quote_strings=True, escape_chars=("\t", "\r", "\n")) def __repr__(self) -> str: return f"{type(self).__name__}({str(self)})" __setitem__ = __setslice__ = __delitem__ = __delslice__ = _disabled pop = append = extend = remove = sort = insert = _disabled