Python:LazyProperty - Revision history

Mwp: /* Lazy Property Decorator */

2018-10-11T02:46:52Z

Lazy Property Decorator

Mwp: /* Python Lazy Property Decorator */

2018-10-11T00:27:08Z

Python Lazy Property Decorator

Mwp: Created page with "= Python Lazy Property Decorator = When a property is both expensive to compute and constant, the LazyProperty decorator may be used to cache the result. import we..."

2018-10-11T00:26:32Z

Created page with "= Python Lazy Property Decorator = When a property is both expensive to compute and constant, the LazyProperty decorator may be used to cache the result. <nowiki> import we..."

New page

= Python Lazy Property Decorator =

When a property is both expensive to compute and constant, the LazyProperty decorator may be used to cache the result.

<nowiki>
import weakref

class LazyProperty(property):
"""LazyProperty is a property that caches its value."""

def __init__(self, fget = None, fset = None, fdel = None, doc = None):
super().__init__(fget, fset, fdel, doc)
self._cache = weakref.WeakKeyDictionary()

def __get__(self, obj, objtype = None):
if not obj in self._cache:
self._cache[obj] = super().__get__(obj, objtype)
return self._cache[obj]

def __set__(self, obj, value):
super().__set__(obj, value)
if obj in self._cache:
# clear cached value
del self._cache[obj]

def __delete__(self, obj):
super().__delete__(obj)
if obj in self._cache:
# clear cached value
del self._cache[obj]
</nowiki>

← Older revision		Revision as of 02:46, 11 October 2018
Line 4:		Line 4:

	<nowiki>		<nowiki>
		+	# This code is licensed under the GPLv3 or later.
		+	# See https://www.gnu.org/licenses/gpl.html for the terms and conditions.
		+
	import weakref		import weakref

← Older revision		Revision as of 00:27, 11 October 2018
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−	= ~~Python~~ Lazy Property Decorator =	+	= Lazy Property Decorator =

	When a property is both expensive to compute and constant, the LazyProperty decorator may be used to cache the result.		When a property is both expensive to compute and constant, the LazyProperty decorator may be used to cache the result.