SF patch #678899: Save time and memory by using itertools in sets module.
diff --git a/Lib/sets.py b/Lib/sets.py
index 6d2c032..5a0167d 100644
--- a/Lib/sets.py
+++ b/Lib/sets.py
@@ -57,7 +57,7 @@
__all__ = ['BaseSet', 'Set', 'ImmutableSet']
-
+from itertools import ifilter
class BaseSet(object):
"""Common base class for mutable and immutable sets."""
@@ -182,7 +182,7 @@
little, big = self, other
else:
little, big = other, self
- common = filter(big._data.has_key, little._data)
+ common = ifilter(big._data.has_key, little)
return self.__class__(common)
def intersection(self, other):
@@ -204,12 +204,10 @@
value = True
selfdata = self._data
otherdata = other._data
- for elt in selfdata:
- if elt not in otherdata:
- data[elt] = value
- for elt in otherdata:
- if elt not in selfdata:
- data[elt] = value
+ for elt in ifilter(otherdata.has_key, selfdata, True):
+ data[elt] = value
+ for elt in ifilter(selfdata.has_key, otherdata, True):
+ data[elt] = value
return result
def symmetric_difference(self, other):
@@ -228,11 +226,9 @@
return NotImplemented
result = self.__class__()
data = result._data
- otherdata = other._data
value = True
- for elt in self:
- if elt not in otherdata:
- data[elt] = value
+ for elt in ifilter(other._data.has_key, self, True):
+ data[elt] = value
return result
def difference(self, other):
@@ -264,10 +260,8 @@
self._binary_sanity_check(other)
if len(self) > len(other): # Fast check for obvious cases
return False
- otherdata = other._data
- for elt in self:
- if elt not in otherdata:
- return False
+ for elt in ifilter(other._data.has_key, self, True):
+ return False
return True
def issuperset(self, other):
@@ -275,9 +269,7 @@
self._binary_sanity_check(other)
if len(self) < len(other): # Fast check for obvious cases
return False
- selfdata = self._data
- for elt in other:
- if elt not in selfdata:
+ for elt in ifilter(self._data.has_key, other, True):
return False
return True