Marc 'BlackJack' Rintsch a écrit : > On Tue, 09 Oct 2007 18:08:34 +0000, Steven D'Aprano wrote: > > >>>>>L = [] >>>>>id(L) >> >>3083496716L >> >>>>>L += [1] >>>>>id(L) >> >>3083496716L >> >>It's the same L, not rebound at all. > > It *is* rebound. To the same object, but it *is* assigned to `L` and not > just mutated in place. > > In [107]: class A: > .....: a = list() > .....: > > In [108]: class B(A): > .....: pass > .....: > > In [109]: B.a += [42] > > In [110]: A.a > Out[110]: [42] > > In [111]: B.a > Out[111]: [42] > > If it was just mutation then `B.a` would have triggered an `AttributeError`.
Nope. >>> class A: ... l = [] ... >>> class B(A): pass ... >>> A.l [] >>> A.l += [1] >>> A.l [1] >>> B.l [1] >>> >>> B.l is A.l True And it is *not* rebound: >>> B.l += [2] >>> A.l [1, 2] >>> B.l [1, 2] >>> A.l is B.l True >>> -- http://mail.python.org/mailman/listinfo/python-list
