MCL/sftools/dev/hostenv/pythontoolsplat: comparison python-2.5.2/win32/Lib/sets.py

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+"""Classes to represent arbitrary sets (including sets of sets).
+This module implements sets using dictionaries whose values are
+ignored.  The usual operations (union, intersection, deletion, etc.)
+are provided as both methods and operators.
+Important: sets are not sequences!  While they support 'x in s',
+'len(s)', and 'for x in s', none of those operations are unique for
+sequences; for example, mappings support all three as well.  The
+characteristic operation for sequences is subscripting with small
+integers: s[i], for i in range(len(s)).  Sets don't support
+subscripting at all.  Also, sequences allow multiple occurrences and
+their elements have a definite order; sets on the other hand don't
+record multiple occurrences and don't remember the order of element
+insertion (which is why they don't support s[i]).
+The following classes are provided:
+BaseSet -- All the operations common to both mutable and immutable
+sets. This is an abstract class, not meant to be directly
+instantiated.
+Set -- Mutable sets, subclass of BaseSet; not hashable.
+ImmutableSet -- Immutable sets, subclass of BaseSet; hashable.
+An iterable argument is mandatory to create an ImmutableSet.
+_TemporarilyImmutableSet -- A wrapper around a Set, hashable,
+giving the same hash value as the immutable set equivalent
+would have.  Do not use this class directly.
+Only hashable objects can be added to a Set. In particular, you cannot
+really add a Set as an element to another Set; if you try, what is
+actually added is an ImmutableSet built from it (it compares equal to
+the one you tried adding).
+When you ask if `x in y' where x is a Set and y is a Set or
+ImmutableSet, x is wrapped into a _TemporarilyImmutableSet z, and
+what's tested is actually `z in y'.
+"""
+# Code history:
+#
+# - Greg V. Wilson wrote the first version, using a different approach
+#   to the mutable/immutable problem, and inheriting from dict.
+#
+# - Alex Martelli modified Greg's version to implement the current
+#   Set/ImmutableSet approach, and make the data an attribute.
+#
+# - Guido van Rossum rewrote much of the code, made some API changes,
+#   and cleaned up the docstrings.
+#
+# - Raymond Hettinger added a number of speedups and other
+#   improvements.
+from __future__ import generators
+try:
+from itertools import ifilter, ifilterfalse
+except ImportError:
+# Code to make the module run under Py2.2
+def ifilter(predicate, iterable):
+if predicate is None:
+def predicate(x):
+return x
+for x in iterable:
+if predicate(x):
+yield x
+def ifilterfalse(predicate, iterable):
+if predicate is None:
+def predicate(x):
+return x
+for x in iterable:
+if not predicate(x):
+yield x
+try:
+True, False
+except NameError:
+True, False = (0==0, 0!=0)
+__all__ = ['BaseSet', 'Set', 'ImmutableSet']
+class BaseSet(object):
+"""Common base class for mutable and immutable sets."""
+__slots__ = ['_data']
+# Constructor
+def __init__(self):
+"""This is an abstract class."""
+# Don't call this from a concrete subclass!
+if self.__class__ is BaseSet:
+raise TypeError, ("BaseSet is an abstract class.  "
+"Use Set or ImmutableSet.")
+# Standard protocols: __len__, __repr__, __str__, __iter__
+def __len__(self):
+"""Return the number of elements of a set."""
+return len(self._data)
+def __repr__(self):
+"""Return string representation of a set.
+This looks like 'Set([<list of elements>])'.
+"""
+return self._repr()
+# __str__ is the same as __repr__
+__str__ = __repr__
+def _repr(self, sorted=False):
+elements = self._data.keys()
+if sorted:
+elements.sort()
+return '%s(%r)' % (self.__class__.__name__, elements)
+def __iter__(self):
+"""Return an iterator over the elements or a set.
+This is the keys iterator for the underlying dict.
+"""
+return self._data.iterkeys()
+# Three-way comparison is not supported.  However, because __eq__ is
+# tried before __cmp__, if Set x == Set y, x.__eq__(y) returns True and
+# then cmp(x, y) returns 0 (Python doesn't actually call __cmp__ in this
+# case).
+def __cmp__(self, other):
+raise TypeError, "can't compare sets using cmp()"
+# Equality comparisons using the underlying dicts.  Mixed-type comparisons
+# are allowed here, where Set == z for non-Set z always returns False,
+# and Set != z always True.  This allows expressions like "x in y" to
+# give the expected result when y is a sequence of mixed types, not
+# raising a pointless TypeError just because y contains a Set, or x is
+# a Set and y contain's a non-set ("in" invokes only __eq__).
+# Subtle:  it would be nicer if __eq__ and __ne__ could return
+# NotImplemented instead of True or False.  Then the other comparand
+# would get a chance to determine the result, and if the other comparand
+# also returned NotImplemented then it would fall back to object address
+# comparison (which would always return False for __eq__ and always
+# True for __ne__).  However, that doesn't work, because this type
+# *also* implements __cmp__:  if, e.g., __eq__ returns NotImplemented,
+# Python tries __cmp__ next, and the __cmp__ here then raises TypeError.
+def __eq__(self, other):
+if isinstance(other, BaseSet):
+return self._data == other._data
+else:
+return False
+def __ne__(self, other):
+if isinstance(other, BaseSet):
+return self._data != other._data
+else:
+return True
+# Copying operations
+def copy(self):
+"""Return a shallow copy of a set."""
+result = self.__class__()
+result._data.update(self._data)
+return result
+__copy__ = copy # For the copy module
+def __deepcopy__(self, memo):
+"""Return a deep copy of a set; used by copy module."""
+# This pre-creates the result and inserts it in the memo
+# early, in case the deep copy recurses into another reference
+# to this same set.  A set can't be an element of itself, but
+# it can certainly contain an object that has a reference to
+# itself.
+from copy import deepcopy
+result = self.__class__()
+memo[id(self)] = result
+data = result._data
+value = True
+for elt in self:
+data[deepcopy(elt, memo)] = value
+return result
+# Standard set operations: union, intersection, both differences.
+# Each has an operator version (e.g. __or__, invoked with |) and a
+# method version (e.g. union).
+# Subtle:  Each pair requires distinct code so that the outcome is
+# correct when the type of other isn't suitable.  For example, if
+# we did "union = __or__" instead, then Set().union(3) would return
+# NotImplemented instead of raising TypeError (albeit that *why* it
+# raises TypeError as-is is also a bit subtle).
+def __or__(self, other):
+"""Return the union of two sets as a new set.
+(I.e. all elements that are in either set.)
+"""
+if not isinstance(other, BaseSet):
+return NotImplemented
+return self.union(other)
+def union(self, other):
+"""Return the union of two sets as a new set.
+(I.e. all elements that are in either set.)
+"""
+result = self.__class__(self)
+result._update(other)
+return result
+def __and__(self, other):
+"""Return the intersection of two sets as a new set.
+(I.e. all elements that are in both sets.)
+"""
+if not isinstance(other, BaseSet):
+return NotImplemented
+return self.intersection(other)
+def intersection(self, other):
+"""Return the intersection of two sets as a new set.
+(I.e. all elements that are in both sets.)
+"""
+if not isinstance(other, BaseSet):
+other = Set(other)
+if len(self) <= len(other):
+little, big = self, other
+else:
+little, big = other, self
+common = ifilter(big._data.has_key, little)
+return self.__class__(common)
+def __xor__(self, other):
+"""Return the symmetric difference of two sets as a new set.
+(I.e. all elements that are in exactly one of the sets.)
+"""
+if not isinstance(other, BaseSet):
+return NotImplemented
+return self.symmetric_difference(other)
+def symmetric_difference(self, other):
+"""Return the symmetric difference of two sets as a new set.
+(I.e. all elements that are in exactly one of the sets.)
+"""
+result = self.__class__()
+data = result._data
+value = True
+selfdata = self._data
+try:
+otherdata = other._data
+except AttributeError:
+otherdata = Set(other)._data
+for elt in ifilterfalse(otherdata.has_key, selfdata):
+data[elt] = value
+for elt in ifilterfalse(selfdata.has_key, otherdata):
+data[elt] = value
+return result
+def  __sub__(self, other):
+"""Return the difference of two sets as a new Set.
+(I.e. all elements that are in this set and not in the other.)
+"""
+if not isinstance(other, BaseSet):
+return NotImplemented
+return self.difference(other)
+def difference(self, other):
+"""Return the difference of two sets as a new Set.
+(I.e. all elements that are in this set and not in the other.)
+"""
+result = self.__class__()
+data = result._data
+try:
+otherdata = other._data
+except AttributeError:
+otherdata = Set(other)._data
+value = True
+for elt in ifilterfalse(otherdata.has_key, self):
+data[elt] = value
+return result
+# Membership test
+def __contains__(self, element):
+"""Report whether an element is a member of a set.
+(Called in response to the expression `element in self'.)
+"""
+try:
+return element in self._data
+except TypeError:
+transform = getattr(element, "__as_temporarily_immutable__", None)
+if transform is None:
+raise # re-raise the TypeError exception we caught
+return transform() in self._data
+# Subset and superset test
+def issubset(self, other):
+"""Report whether another set contains this set."""
+self._binary_sanity_check(other)
+if len(self) > len(other):  # Fast check for obvious cases
+return False
+for elt in ifilterfalse(other._data.has_key, self):
+return False
+return True
+def issuperset(self, other):
+"""Report whether this set contains another set."""
+self._binary_sanity_check(other)
+if len(self) < len(other):  # Fast check for obvious cases
+return False
+for elt in ifilterfalse(self._data.has_key, other):
+return False
+return True
+# Inequality comparisons using the is-subset relation.
+__le__ = issubset
+__ge__ = issuperset
+def __lt__(self, other):
+self._binary_sanity_check(other)
+return len(self) < len(other) and self.issubset(other)
+def __gt__(self, other):
+self._binary_sanity_check(other)
+return len(self) > len(other) and self.issuperset(other)
+# Assorted helpers
+def _binary_sanity_check(self, other):
+# Check that the other argument to a binary operation is also
+# a set, raising a TypeError otherwise.
+if not isinstance(other, BaseSet):
+raise TypeError, "Binary operation only permitted between sets"
+def _compute_hash(self):
+# Calculate hash code for a set by xor'ing the hash codes of
+# the elements.  This ensures that the hash code does not depend
+# on the order in which elements are added to the set.  This is
+# not called __hash__ because a BaseSet should not be hashable;
+# only an ImmutableSet is hashable.
+result = 0
+for elt in self:
+result ^= hash(elt)
+return result
+def _update(self, iterable):
+# The main loop for update() and the subclass __init__() methods.
+data = self._data
+# Use the fast update() method when a dictionary is available.
+if isinstance(iterable, BaseSet):
+data.update(iterable._data)
+return
+value = True
+if type(iterable) in (list, tuple, xrange):
+# Optimized: we know that __iter__() and next() can't
+# raise TypeError, so we can move 'try:' out of the loop.
+it = iter(iterable)
+while True:
+try:
+for element in it:
+data[element] = value
+return
+except TypeError:
+transform = getattr(element, "__as_immutable__", None)
+if transform is None:
+raise # re-raise the TypeError exception we caught
+data[transform()] = value
+else:
+# Safe: only catch TypeError where intended
+for element in iterable:
+try:
+data[element] = value
+except TypeError:
+transform = getattr(element, "__as_immutable__", None)
+if transform is None:
+raise # re-raise the TypeError exception we caught
+data[transform()] = value
+class ImmutableSet(BaseSet):
+"""Immutable set class."""
+__slots__ = ['_hashcode']
+# BaseSet + hashing
+def __init__(self, iterable=None):
+"""Construct an immutable set from an optional iterable."""
+self._hashcode = None
+self._data = {}
+if iterable is not None:
+self._update(iterable)
+def __hash__(self):
+if self._hashcode is None:
+self._hashcode = self._compute_hash()
+return self._hashcode
+def __getstate__(self):
+return self._data, self._hashcode
+def __setstate__(self, state):
+self._data, self._hashcode = state
+class Set(BaseSet):
+""" Mutable set class."""
+__slots__ = []
+# BaseSet + operations requiring mutability; no hashing
+def __init__(self, iterable=None):
+"""Construct a set from an optional iterable."""
+self._data = {}
+if iterable is not None:
+self._update(iterable)
+def __getstate__(self):
+# getstate's results are ignored if it is not
+return self._data,
+def __setstate__(self, data):
+self._data, = data
+def __hash__(self):
+"""A Set cannot be hashed."""
+# We inherit object.__hash__, so we must deny this explicitly
+raise TypeError, "Can't hash a Set, only an ImmutableSet."
+# In-place union, intersection, differences.
+# Subtle:  The xyz_update() functions deliberately return None,
+# as do all mutating operations on built-in container types.
+# The __xyz__ spellings have to return self, though.
+def __ior__(self, other):
+"""Update a set with the union of itself and another."""
+self._binary_sanity_check(other)
+self._data.update(other._data)
+return self
+def union_update(self, other):
+"""Update a set with the union of itself and another."""
+self._update(other)
+def __iand__(self, other):
+"""Update a set with the intersection of itself and another."""
+self._binary_sanity_check(other)
+self._data = (self & other)._data
+return self
+def intersection_update(self, other):
+"""Update a set with the intersection of itself and another."""
+if isinstance(other, BaseSet):
+self &= other
+else:
+self._data = (self.intersection(other))._data
+def __ixor__(self, other):
+"""Update a set with the symmetric difference of itself and another."""
+self._binary_sanity_check(other)
+self.symmetric_difference_update(other)
+return self
+def symmetric_difference_update(self, other):
+"""Update a set with the symmetric difference of itself and another."""
+data = self._data
+value = True
+if not isinstance(other, BaseSet):
+other = Set(other)
+if self is other:
+self.clear()
+for elt in other:
+if elt in data:
+del data[elt]
+else:
+data[elt] = value
+def __isub__(self, other):
+"""Remove all elements of another set from this set."""
+self._binary_sanity_check(other)
+self.difference_update(other)
+return self
+def difference_update(self, other):
+"""Remove all elements of another set from this set."""
+data = self._data
+if not isinstance(other, BaseSet):
+other = Set(other)
+if self is other:
+self.clear()
+for elt in ifilter(data.has_key, other):
+del data[elt]
+# Python dict-like mass mutations: update, clear
+def update(self, iterable):
+"""Add all values from an iterable (such as a list or file)."""
+self._update(iterable)
+def clear(self):
+"""Remove all elements from this set."""
+self._data.clear()
+# Single-element mutations: add, remove, discard
+def add(self, element):
+"""Add an element to a set.
+This has no effect if the element is already present.
+"""
+try:
+self._data[element] = True
+except TypeError:
+transform = getattr(element, "__as_immutable__", None)
+if transform is None:
+raise # re-raise the TypeError exception we caught
+self._data[transform()] = True
+def remove(self, element):
+"""Remove an element from a set; it must be a member.
+If the element is not a member, raise a KeyError.
+"""
+try:
+del self._data[element]
+except TypeError:
+transform = getattr(element, "__as_temporarily_immutable__", None)
+if transform is None:
+raise # re-raise the TypeError exception we caught
+del self._data[transform()]
+def discard(self, element):
+"""Remove an element from a set if it is a member.
+If the element is not a member, do nothing.
+"""
+try:
+self.remove(element)
+except KeyError:
+pass
+def pop(self):
+"""Remove and return an arbitrary set element."""
+return self._data.popitem()[0]
+def __as_immutable__(self):
+# Return a copy of self as an immutable set
+return ImmutableSet(self)
+def __as_temporarily_immutable__(self):
+# Return self wrapped in a temporarily immutable set
+return _TemporarilyImmutableSet(self)
+class _TemporarilyImmutableSet(BaseSet):
+# Wrap a mutable set as if it was temporarily immutable.
+# This only supplies hashing and equality comparisons.
+def __init__(self, set):
+self._set = set
+self._data = set._data  # Needed by ImmutableSet.__eq__()
+def __hash__(self):
+return self._set._compute_hash()