bokr at oz.net
Thu Mar 27 04:28:43 CET 2003
On Wed, 26 Mar 2003 12:38:25 GMT, Alex Martelli <aleax at aleax.it> wrote:
>Daniel Timothy Bentley wrote:
>> Basically, if you're going to say ints and longs are separate types, I
>> think there should be a way to makes ints from longs fairly reliably. I
>> don't think that's a niche, I think it's something a consistent language
>> should provice.
>Well, your proposed expression DOES "make ints from longs fairly reliably",
>it's just that I think the ints it makes are probably not the ones you'd
>like to get (except for 0<=foo<sys.maxint).
>I think you want something like: int(cmp(foo,0)*(abs(foo) & sys.maxint)).
>Me, I think it's better to incapsulate the "conversion to int ignoring
>overflow" in a function, using an if/else:
> if foo>=0: return int(foo&sys.maxint)
> else: return -int(-foo&sys.maxint)
The above doesn't match typical hardware and C-style int behavior:
>>> import sys
>>> def toint(foo):
... if foo>=0: return int(foo&sys.maxint)
... else: return -int(-foo&sys.maxint)
Because two's complement "minint" is not -sys.maxint,
(it is -sys.maxint-1)
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