memoized_property

A simple python decorator for defining properties that only run their fget function once.

• Free software: BSD license

What?

A Python property that only calls its fget function one time. How many times have you written this code (or similar)?

def class C(object):

    @property
    def name(self):
        if not hasattr(self, '_name'):
            self._name = some_expensive_load()
        return self._name

I've written it just enough times to be annoyed enough to capture this module. The result is this:

from memoized_property import memoized_property

def class C(object):

    @memoized_property
    def name(self):
        # Boilerplate guard conditional avoided, but this is still only called once
        return some_expensive_load()

Why?

I couldn't find a pre-existing version of this on PyPI. I found one other on GitHub, https://github.com/ytyng/python-memoized-property, but it was not published to PyPI.