Source code for utool.util_set

# -*- coding: utf-8 -*-
from __future__ import absolute_import, division, print_function
from six.moves import zip, map, range  # NOQA
import collections
import weakref
from utool import util_inject
print, print_, printDBG, rrr, profile = util_inject.inject(__name__, '[set]')


class _Link(object):
    __slots__ = 'prev', 'next', 'key', '__weakref__'


[docs]class OrderedSet(collections.MutableSet): """ Set the remembers the order elements were added Big-O running times for all methods are the same as for regular sets. The internal self.__map dictionary maps keys to links in a doubly linked list. The circular doubly linked list starts and ends with a sentinel element. The sentinel element never gets deleted (this simplifies the algorithm). The prev/next links are weakref proxies (to prevent circular references). Individual links are kept alive by the hard reference in self.__map. Those hard references disappear when a key is deleted from an OrderedSet. References: http://code.activestate.com/recipes/576696/ http://code.activestate.com/recipes/576694/ http://stackoverflow.com/questions/1653970/does-python-have-an-ordered-set """ def __init__(self, iterable=None): self.__root = root = _Link() # sentinel node for doubly linked list root.prev = root.next = root self.__map = {} # key --> link if iterable is not None: self |= iterable def __len__(self): return len(self.__map) def __contains__(self, key): return key in self.__map
[docs] def add(self, key): # Store new key in a new link at the end of the linked list if key not in self.__map: self.__map[key] = link = _Link() root = self.__root last = root.prev link.prev, link.next, link.key = last, root, key last.next = root.prev = weakref.proxy(link)
[docs] def append(self, key): # Alias for add return self.add(key)
[docs] def discard(self, key): # Remove an existing item using self.__map to find the link which is # then removed by updating the links in the predecessor and successors. if key in self.__map: link = self.__map.pop(key) link.prev.next = link.next link.next.prev = link.prev
def __iter__(self): # Traverse the linked list in order. root = self.__root curr = root.next while curr is not root: yield curr.key curr = curr.next def __reversed__(self): # Traverse the linked list in reverse order. root = self.__root curr = root.prev while curr is not root: yield curr.key curr = curr.prev
[docs] def pop(self, last=True): if not self: raise KeyError('set is empty') key = next(reversed(self)) if last else next(iter(self)) self.discard(key) return key
def __repr__(self): if not self: return '%s()' % (self.__class__.__name__,) return '%s(%r)' % (self.__class__.__name__, list(self)) def __eq__(self, other): if isinstance(other, OrderedSet): return len(self) == len(other) and list(self) == list(other) return not self.isdisjoint(other) # alias
oset = OrderedSet