[Python-checkins] r59892 - in python/trunk: Doc/library/collections.rst Lib/collections.py
raymond.hettinger
python-checkins at python.org
Thu Jan 10 20:15:10 CET 2008
Author: raymond.hettinger
Date: Thu Jan 10 20:15:10 2008
New Revision: 59892
Modified:
python/trunk/Doc/library/collections.rst
python/trunk/Lib/collections.py
Log:
Examples for named tuple subclassing should include __slots__
Modified: python/trunk/Doc/library/collections.rst
==============================================================================
--- python/trunk/Doc/library/collections.rst (original)
+++ python/trunk/Doc/library/collections.rst Thu Jan 10 20:15:10 2008
@@ -513,23 +513,24 @@
a fixed-width print format::
>>> class Point(namedtuple('Point', 'x y')):
+ ... __slots__ = ()
... @property
... def hypot(self):
... return (self.x ** 2 + self.y ** 2) ** 0.5
... def __str__(self):
... return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % (self.x, self.y, self.hypot)
- >>> for p in Point(3,4), Point(14,5), Point(9./7,6):
+ >>> for p in Point(3, 4), Point(14, 5/7.):
... print p
Point: x= 3.000 y= 4.000 hypot= 5.000
- Point: x=14.000 y= 5.000 hypot=14.866
- Point: x= 1.286 y= 6.000 hypot= 6.136
+ Point: x=14.000 y= 0.714 hypot=14.018
Another use for subclassing is to replace performance critcal methods with
faster versions that bypass error-checking and that localize variable access::
class Point(namedtuple('Point', 'x y')):
+ __slots__ = ()
_make = classmethod(tuple.__new__)
def _replace(self, _map=map, **kwds):
return self._make(_map(kwds.get, ('x', 'y'), self))
Modified: python/trunk/Lib/collections.py
==============================================================================
--- python/trunk/Lib/collections.py (original)
+++ python/trunk/Lib/collections.py Thu Jan 10 20:15:10 2008
@@ -118,17 +118,19 @@
# test and demonstrate ability to override methods
class Point(namedtuple('Point', 'x y')):
+ __slots__ = ()
@property
def hypot(self):
return (self.x ** 2 + self.y ** 2) ** 0.5
def __str__(self):
return 'Point: x=%6.3f y=%6.3f hypot=%6.3f' % (self.x, self.y, self.hypot)
- for p in Point(3,4), Point(14,5), Point(9./7,6):
+ for p in Point(3, 4), Point(14, 5/7.):
print p
class Point(namedtuple('Point', 'x y')):
'Point class with optimized _make() and _replace() without error-checking'
+ __slots__ = ()
_make = classmethod(tuple.__new__)
def _replace(self, _map=map, **kwds):
return self._make(_map(kwds.get, ('x', 'y'), self))
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