Nested list problem - please...

Andreas Waldenburger usenot at geekmail.INVALID
Sun Apr 18 10:43:57 EDT 2010

On Sat, 17 Apr 2010 13:31:54 -0700 Chris Rebert <clp2 at>

> On Sat, Apr 17, 2010 at 12:40 PM, Martin Hvidberg
> <Martin at> wrote:
> > I have this code, it builds up a data structure of nested lists,
> > and filling data in them. My problem is that it seems that one of
> > the lists SA[1] is not a list of unique instances but rather
> > individual links to the same variable. In the example below I
> > assign 'X' to what I intended to be the first Compounds Name. But
> > rather the 'X' goes into all the Compounds Name. I thought that the
> > [:] in SAdata.extend([CP[:]]) would ensure copies rather than links
> > to. What is going wrong?  
> someList[:] only copies 1-level deep. If you have a list of lists,
> none of the inner lists will be copied; you'll get a new list of
> references to the same lists instead. I think your code assumes [:]
> copies lists recursively.

Expanding on that, Martin, I think "from copy import deepcopy" should
solve that problem.



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