0e2a567b90
Since the existing set and frozen sets are pickleable so should this type so that it functions and matches how the the existing types work. Change-Id: I6994b868ecbf0428ab4bc8ab5c2f4486ad53fb49
142 lines
4.1 KiB
Python
142 lines
4.1 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import collections
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import itertools
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try:
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from collections import OrderedDict # noqa
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except ImportError:
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from ordereddict import OrderedDict # noqa
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import six
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# Used for values that don't matter in sets backed by dicts...
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_sentinel = object()
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def _merge_in(target, iterable=None, sentinel=_sentinel):
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"""Merges iterable into the target and returns the target."""
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if iterable is not None:
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for value in iterable:
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target.setdefault(value, sentinel)
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return target
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class OrderedSet(collections.Set, collections.Hashable):
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"""A read-only hashable set that retains insertion/initial ordering.
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It should work in all existing places that ``frozenset`` is used.
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See: https://mail.python.org/pipermail/python-ideas/2009-May/004567.html
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for an idea thread that *may* eventually (*someday*) result in this (or
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similar) code being included in the mainline python codebase (although
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the end result of that thread is somewhat discouraging in that regard).
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"""
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__slots__ = ['_data']
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def __init__(self, iterable=None):
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self._data = _merge_in(OrderedDict(), iterable)
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def __hash__(self):
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return self._hash()
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def __contains__(self, value):
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return value in self._data
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def __len__(self):
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return len(self._data)
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def __iter__(self):
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for value in six.iterkeys(self._data):
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yield value
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def __setstate__(self, items):
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self.__init__(iterable=iter(items))
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def __getstate__(self):
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return tuple(self)
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def __repr__(self):
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return "%s(%s)" % (type(self).__name__, list(self))
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def copy(self):
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"""Return a shallow copy of a set."""
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it = iter(self)
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c = self._from_iterable(it)
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return c
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def intersection(self, *sets):
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"""Return the intersection of two or more sets as a new set.
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(i.e. elements that are common to all of the sets.)
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"""
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def absorb_it(sets):
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for value in iter(self):
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matches = 0
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for s in sets:
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if value in s:
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matches += 1
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else:
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break
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if matches == len(sets):
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yield value
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it = absorb_it(sets)
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c = self._from_iterable(it)
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return c
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def issuperset(self, other):
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"""Report whether this set contains another set."""
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for value in other:
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if value not in self:
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return False
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return True
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def issubset(self, other):
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"""Report whether another set contains this set."""
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for value in iter(self):
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if value not in other:
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return False
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return True
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def difference(self, *sets):
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"""Return the difference of two or more sets as a new set.
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(i.e. all elements that are in this set but not the others.)
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"""
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def absorb_it(sets):
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for value in iter(self):
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seen = False
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for s in sets:
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if value in s:
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seen = True
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break
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if not seen:
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yield value
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it = absorb_it(sets)
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c = self._from_iterable(it)
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return c
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def union(self, *sets):
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"""Return the union of sets as a new set.
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(i.e. all elements that are in either set.)
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"""
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it = itertools.chain(iter(self), *sets)
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return self._from_iterable(it)
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