update certain key-value pairs of a dict from another dict

[Tim Chase]

On 2016-11-11 13:29, Peter Otten wrote:
> The same using update(), with a generator expression that avoids
> the intermediate dict:
> 
> >>> dict1 = {'A': 'a', 'B': 'b', 'C': 'c'}
> >>> dict1.update((k, dict2[k]) for k in desired & dict1.keys() & 
> dict2.keys())

Huh.  Handy to file that new knowledge away.  I'd not realized it
could take a 2-tuple iterable, but my previous example would then be
more cleanly written as

  dict1.update((k,v) for k,v in dict.items() if k in desired)

But yes, certainly a couple edge cases depending on the dict
sizes, the size of the "desired" set, and what should happen in the
event dict2 (or "desired") has keys that dict1 doesn't.

-tkc