skipping __init__ and using exploiting a class member instead
Ned Batchelder
ned at nedbatchelder.com
Sat Oct 19 17:55:57 EDT 2013
On 10/19/13 5:44 PM, Peter Cacioppi wrote:
> Is the following considered poor Python form?
>
> class Foo (object) :
> _lazy = None
> def foo(self, x) :
> _lazy = _lazy or self.get_something(x)
> def get_something(self, x) :
> # doesn't really matter
>
> I like this idiom for certain situations, just wondering if it will raise the hackles of other Pythonistas.
>
> I use this idiom sparingly, but sometimes it just fits the task at hand, I hear Guidos voice saying "use the Force" in my ear, etc.
You present this as a choice between __init__ or a class attribute, but
those two things are very different. Is your intent to have an instance
attribute, or a class attribute? Lazily populated instance attributes
are fine, I would do it like this:
class Foo(object):
def __init__(self):
self._lazy = None
def foo(self, x):
if self._lazy is None:
self._lazy = self.get_something(x)
...
--Ned.
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