decouple copy of a list

[Wolfgang Rohdewald]

On Freitag 10 Dezember 2010, Dirk Nachbar wrote:
> > b=a[:]
> > 
> > --
> > Wolfgang
> 
> I did that but then some things I do with b happen to a as
> well.

as others said, this is no deep copy. So if you do something
to an element in b, and if the same element is in a, both
are changed as they are still the same objects:

>>> x,y=5,6
>>> a=[x,y]
>>> b=a[:]
>>> id(a),id(b)
(140695481867368, 140695481867512)
>>> id(a[0]),id(b[0])
(33530584, 33530584)
>>> a=b
>>> id(a),id(b)
(140695481867512, 140695481867512)


-- 
Wolfgang