Chris Rebert wrote: > On Thu, Apr 1, 2010 at 3:34 PM, kj <no.em...@please.post> wrote: >> When coding C I have often found static local variables useful for >> doing once-only run-time initializations. > <snip> >> Another approach would be to stuff the static values in the function's >> __dict__. This is less satisfactory than the closure approach >> because the "pseudo-static" variable is accessible from outside >> the function, but the code is arguably a little more straightforward, >> and one does not end up with the now useless one-time closure-generating >> function kicking around. Here's another version of the function >> above: >> >>>>> def spam(): >> ... d = spam.__dict__ >> ... if not 's' in spam.__dict__: >> ... spam.s = 1 >> ... print spam.s >> ... spam.s += 1 >> ... >>>>> spam() >> 1 >>>>> spam() >> 2 >>>>> spam() >> 3 >> >> Besides the external accessibility issue, I don't like explictly >> coding the name of the function within the function. Is there any >> way to have the function access its own __dict__ without having to >> explicitly code its name in its body? E.g., is there some generic >> special variable that, within a function, refers to the function >> object itself? > > Nope. It's been proposed in that past > (http://www.python.org/dev/peps/pep-3130/), but that proposal was > rejected. > >> I'm sure that there are many other ways to skin this cat, especially >> if one starts definining fancy callable classes and whatnot. But >> is there a better *simple* way to achieve C-style static locals in >> Python that does not require a lot of extra machinery? > > You can abuse the default argument value mechanism: > > def spam(s_cell=[1]): > s = s_cell[0] > print s > s_cell[0] += 1 > > It's a bit less ugly when the value itself is mutable, which isn't the > case here with the integer. > > Personally, I hate such abuse with a passion; I think a global > variable is clearest.
But the real problem is that the OP is insisting on using purely procedural Python when the problem is screaming for an object-oriented answer. If the function were instead a method then the instance namespace would be the logical place to store the required data. regards Steve regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 See PyCon Talks from Atlanta 2010 http://pycon.blip.tv/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS: http://holdenweb.eventbrite.com/ -- http://mail.python.org/mailman/listinfo/python-list
