Marc 'BlackJack' Rintsch wrote:
> In <[EMAIL PROTECTED]>, SpreadTooThin
> wrote:
>
> > I'm really worried that python may is doing some things I wasn't
> > expecting... but lets see...
>
> Expect that Python never copies something if don't ask explicitly for a
> copy.
>
> > if I pass a list to a function def fn(myList):
> >
> > and in that function I modify an element in the list, then does the
> > callers list get modied as well.
> >
> > def fn(list):
> > list[1] = 0
> >
> > myList = [1, 2, 3]
> > print myList
> > fn(myList)
> > print myList
> >
> >>>> [1,2,3]
> >>>> [1,0,3]
> >
> > How can I avoid this? In this case this is a really simplified example
> > but the effects are the same...
>
> In this case:
>
> def fn(lst):
> lst = list(lst)
> lst[1] = 0
>
>
> > How do I specify or create deep copies of objects that may contain
> > other objects that may contain other object that may contain other
> > objects....
>
> See the `copy` module especially `copy.deepcopy()`.
>
This appears to be the right thing to do to me.. (but what do I know?)
I tried this which more closely resembles my project but this doesn't
work:
import array
import copy
class test:
def __init__(self):
self.a = array.array('H', [1, 2, 3])
self.b = ['a', 'b', 'c']
def dump(self):
print self.a, self.b
t = test()
t.dump()
def testit(x):
t = copy.deepcopy(x)
t.a[1] = 0
t.b[1] = 0
testit(t)
t.dump()
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