Using csv DictWriter - add a extra field

[Peter Otten]

Victor Hooi wrote:

> Aha, yeah, I can add the connection_id as another field in the inner dict
> - the only drawback is that the data is duplicated twice. However, I
> suppose even if it's not elegant, it does work.

The elegance lies in its simplicity, so it's still my personal favourite.

> However, that ChainMap does look interesting =). And yes, I am actually
> using Python 3.x (mainly because of http://bugs.python.org/issue6641).
> 
> So if I understand correctly, I can just use ChainMap to join any
> arbitrary number of dicts together - it seems like the right solution
> here.
> 
> Are there any drawbacks to using ChainMap here? (Aside from needing Python
> 3.x).

As it introduces another level of indirection it costs a little time, but 
compared to the actual I/O that should be negligible. 

So no, if there is a drawback I don't see it.