lists and append, and loop iteration

[Janko Hauser]

Charles G Waldman <cgw at fnal.gov> writes:

> I would write 
> 
>  dict['new_key'] = dict.get('new_key',[]) + [new_value]
> 
This is a trick, because it does only supress the exception. But has
the same effect :-)

I could not write
>>> dict={}
>>> dict['new_key'] = dict.get('new_key',[]).append(['new_value'])
>>> dict
{'new_key': None}

To this refered my last note about the reference of a. Although I do
not understand this. If I get not an empty list, why can I do an
append?

Questioned,

__Janko



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