Re: [Python-ideas] Dict joining using + and +=

On 3/4/19 10:44 AM, Steven D'Aprano wrote:

If you know ahead of time which order you want, you can simply reverse it:

 # prefs = site_defaults + user_defaults + document_prefs
 prefs = dict(ChainMap(document_prefs, user_defaults, site_defaults))

but that seems a little awkward to me, and reads backwards. I'm used to thinking reading left-to-right, not right-to-left.

I read that as use document preferences first, then user defaults, then site defautls, exactly as I'd explain the functionality to someone else.

So maybe we're agreeing: if you think in terms of updating a dictionary of preferences, then maybe it reads backwards, but if you think of implementing features, then adding dictionaries of preferences reads backwards.