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Re: lazy properties?

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  Re: lazy properties? Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-01 15:52 -0600
    Re: lazy properties? Miki Tebeka <miki.tebeka@gmail.com> - 2012-11-01 16:30 -0700
    Re: lazy properties? Miki Tebeka <miki.tebeka@gmail.com> - 2012-11-01 16:30 -0700

#32573 — Re: lazy properties?

On Thu, Nov 1, 2012 at 3:38 PM, Andrea Crotti <andrea.crotti.0@gmail.com> wrote:
> What I would like to write is
>     @lazy_property
>     def var_lazy(self):
>         return long_computation()
>
> and this should imply that the long_computation is called only once..

If you're using Python 3.2+, then functools.lru_cache probably
suffices for your needs.

@property
@functools.lru_cache()
def var_lazy(self):
    return long_computation()

If you really need to shorten that to a single declaration:

def lazy_property(func):
    return property(functools.lru_cache()(func))

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#32580

> If you're using Python 3.2+, then functools.lru_cache probably
> ...
And if you're on 2.X, you can grab lru_cache from http://code.activestate.com/recipes/498245-lru-and-lfu-cache-decorators/

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#32581

> If you're using Python 3.2+, then functools.lru_cache probably
> ...
And if you're on 2.X, you can grab lru_cache from http://code.activestate.com/recipes/498245-lru-and-lfu-cache-decorators/

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