Memoized Property Performance Test

gistfile1.txt

import timeit

class reify(object):
    def __init__(self, wrapped):
        self.wrapped = wrapped
        try:
            self.__doc__ = wrapped.__doc__
        except: # pragma: no cover
            pass

    def __get__(self, inst, objtype=None):
        if inst is None:
            return self
        val = self.wrapped(inst)
        setattr(inst, self.wrapped.__name__, val)
        return val


class memoized_property:
    """A read-only @property that is only evaluated once."""
    def __init__(self, fget, doc=None):
        self.counter = 10
        self.fget = fget
        self.__doc__ = doc or fget.__doc__
        self.__name__ = fget.__name__

    def __get__(self, obj, cls):
        if obj is None:
            return self
        result = self.fget(obj) 
        setattr(obj, self.__name__, result)

        self.counter += 1
        print(self.counter)
        return result


class Test1:

    def __init__(self):
        self._title = 'dowwie'

    @memoized_property
    def title(self):
        if not hasattr(self, '_title'):
            self._title = 'default'

        return self._title


class Test2:

    def __init__(self):
        self._title = 'dowwie'

    @property
    def title(self):
        if not hasattr(self, '_title'):
            self._title = 'default'
        return self._title


class Test3:

    def __init__(self):
        self._title = 'dowwie'

    @reify
    def title(self):
        if not hasattr(self, '_title'):
            self._title = 'default'

        return self._title


t1 = Test1()
t2 = Test2()
t3 = Test3()

memoized = min(timeit.repeat("t1.title", setup="from __main__ import t1", repeat=3, number=1000000))
reified = min(timeit.repeat("t3.title", setup="from __main__ import t3", repeat=3, number=1000000))
oldproperty = min(timeit.repeat("t2.title", setup="from __main__ import t2", repeat=3, number=1000000))

print('memoized:  ', memoized)
print('reify: ', reified)
print('oldproperty: ', oldproperty)


Results
----------
memoized:   0.02977088201441802
reify:  0.027064872003393248
oldproperty:  0.15724623799906112