On Nov 21, 3:11 am, Duncan Booth <[EMAIL PROTECTED]> wrote: > Steven D'Aprano <[EMAIL PROTECTED]> wrote: > > On Fri, 21 Nov 2008 03:32:25 +0000, Steven D'Aprano wrote: > > >>> Rather it seems to me that the essence of the idea they had in mind > >>> is that call-by-value is equivalent to assignment. > > >> You've just *assumed* that assignment in Algol 60 doesn't involving > >> copying. Based on the very little I know about Algol, I think that is > >> a very unsafe assumption. I know significantly more about Pascal, and > >> in Pascal, assignment *is* copying. > > >> (I wait now with bated breath for somebody to point out some Python > >> implementation or feature where assignment doesn't make a copy...) > > > Ah crap, I meant *Pascal*. Python of course doesn't copy objects when > > you assign them. > > I think you meant "Python of course doesn't copy objects when you rebind > names". Python can (and sometimes does) make copies of objects when you > assign them, , but only if the assignment involves something other than > simply rebinding a name. e.g. > > a[:] = [1, 2, 3]
No, that's not assignment, it's syntactic sugar for a __setslice__ call. No copies here. -- http://mail.python.org/mailman/listinfo/python-list
