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Improvements to set.py:

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* Relaxed the argument restrictions for non-operator methods.  They now
  allow any iterable instead of requiring a set.  This makes the module
  a little easier to use and paves the way for an efficient C
  implementation which can take better advantage of iterable arguments
  while screening out immutables.

* Deprecated Set.update() because it now duplicates Set.union_update()

* Adapted the tests and docs to include the above changes.

* Added more test coverage including testing identities and checking
  to make sure non-restartable generators work as arguments.

Will backport to Py2.3.1 so that the interface remains consistent
across versions.  The deprecation of update() will be changed to
a FutureWarning.
This commit is contained in:
Raymond Hettinger 2003-08-17 08:34:09 +00:00
parent 236ffba400
commit 6a1801271a
4 changed files with 216 additions and 56 deletions
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101
Lib/sets.py
View file

@ -196,17 +196,16 @@ class BaseSet(object):
"""
if not isinstance(other, BaseSet):
return NotImplemented
result = self.__class__()
result._data = self._data.copy()
result._data.update(other._data)
return result
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.)
"""
return self | other
result = self.__class__(self)
result._update(other)
return result
def __and__(self, other):
"""Return the intersection of two sets as a new set.
@ -215,19 +214,21 @@ class BaseSet(object):
"""
if not isinstance(other, BaseSet):
return NotImplemented
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)
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.)
"""
return self & other
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.
@ -236,23 +237,26 @@ class BaseSet(object):
"""
if not isinstance(other, BaseSet):
return NotImplemented
result = self.__class__()
data = result._data
value = True
selfdata = self._data
otherdata = 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
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.)
"""
return self ^ other
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.
@ -261,19 +265,23 @@ class BaseSet(object):
"""
if not isinstance(other, BaseSet):
return NotImplemented
result = self.__class__()
data = result._data
value = True
for elt in ifilterfalse(other._data.has_key, self):
data[elt] = value
return result
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.)
"""
return self - 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
@ -441,7 +449,7 @@ class Set(BaseSet):
def union_update(self, other):
"""Update a set with the union of itself and another."""
self |= other
self._update(other)
def __iand__(self, other):
"""Update a set with the intersection of itself and another."""
@ -451,40 +459,51 @@ class Set(BaseSet):
def intersection_update(self, other):
"""Update a set with the intersection of itself and another."""
self &= other
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)
for elt in other:
if elt in data:
del data[elt]
else:
data[elt] = value
return self
def symmetric_difference_update(self, other):
"""Update a set with the symmetric difference of itself and another."""
self ^= other
def __isub__(self, other):
"""Remove all elements of another set from this set."""
self._binary_sanity_check(other)
data = self._data
for elt in ifilter(data.has_key, other):
del data[elt]
self.difference_update(other)
return self
def difference_update(self, other):
"""Remove all elements of another set from this set."""
self -= other
data = self._data
if not isinstance(other, BaseSet):
other = Set(other)
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)."""
import warnings
warnings.warn("The update() method deprecated; "
"Use union_update() instead",
DeprecationWarning)
self._update(iterable)
def clear(self):