A cached-property for decorating methods in classes.
Project description
A cached-property for decorating methods in classes.
Free software: BSD license
Documentation: http://cached-property.rtfd.org.
Why?
Makes caching of time or computational expensive properties quick and easy.
Because I got tired of copy/pasting this code from non-web project to non-web project.
I needed something really simple that worked in Python 2 and 3.
How to use it
Define a class with an expensive property. Every time you stay there the price goes up by $50. I
class Monopoly(object):
def __init__(self):
self.boardwalk_price = 500
@property
def boardwalk(self):
# In reality, this might represent a database call or time
# intensive task like calling a third-party API.
self.boardwalk_price += 50
return self.boardwalk_price
Now run it:
>>> m = Monopoly()
>>> m.boardwalk
550
>>> m.boardwalk
600
Let’s convert the boardwalk property into a cached_property.
from cached_property import cached_property
class Monopoly(object):
def __init__(self):
self.boardwalk_price = 500
@property
def cached_property(self):
# Again, this is a silly example. Don't worry about it, this is
# just an example for clarity.
self.boardwalk_price += 50
return self.boardwalk_price
Now when we run it the price stays at $550.
>>> m = Monopoly()
>>> m.boardwalk
550
>>> m.boardwalk
550
>>> m.boardwalk
550
Why doesn’t the value of m.boardwalk change? Because it’s a cached property!
Credits
Django, Werkzueg, Bottle, and Zope for having their own implementations. This package uses the Django version.
Reinout Van Rees for pointing out the cached_property decorator to me.
My awesome wife Audrey who created cookiecutter, which meant rolling this out took me just 15 minutes.
History
0.1.1 (2014-05-17)
setup.py fix. Whoops!
0.1.0 (2014-05-17)
First release on PyPI.
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
Built Distribution
Hashes for cached_property-0.1.1-py2.py3-none-any.whl
Algorithm | Hash digest | |
---|---|---|
SHA256 | 848e62a6c59b0b8f705492ccf173f81c54614a5411d88137bade7fb2aa7f193a |
|
MD5 | 1cd52352078af95ab47dead06fa74109 |
|
BLAKE2b-256 | 7b95724b6c91ab5b7c95d18734162a602eba68b493b43ef4f86f1c7b770cbd88 |