On Thu, Apr 9, 2009 at 12:16 PM, andrew cooke <and...@acooke.org> wrote:
> but when you need to access instances by more than one value (.bar and > .baz) then typically that's a hard problem, and there's a trade-off > somewhere. you might find writing a special container that contains two > dicts is useful. if so, you might want to use weak references - see > weakref module). > > all the above are relatively direct solutions. in my experience this kind > of issue often comes from not thinking at a high enough level about the > algorithm - even though my third suggestion (deque) sounds rather obscure > you may find that once you look at you algorithm more carefully it can be > rewritten in that way. i think i've seen this in my own code as i improve > at integrating what might be more "functional" idioms into python in a > "natural" (pythonic) way. > > andrew > > Thanks, I have used a dict for doing what I was talking about in cases where I only ever want to be able to access by one property of the objects, but as you know, that doesn't work too well when I want to access by more than one property. It looks like I need to write a special class that acts as an iterable, and as a map on values of (more-or-less) arbitrary properties of the objects contained in it. I could probably also use with stepping back and looking at my problem from a higher level to make sure I'm not barking up an entirely wrong tree. I'll take a look at weakref and dequeue, and see if they help.
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