[Python-Dev] dict.supplement() (was Re: list.shift()) (original) (raw)

Fred L. Drake, Jr. fdrake@acm.org
Mon, 20 Mar 2000 14:02:48 -0500 (EST)

Peter Funk writes:

Ouppss... I should have tested this before posting. But currently I use the more explicit (and probably slower version) in my code:

The performance is based entirely on the size of each; in the (probably typical) case of smallish dictionaries (<50 entries), it's probably cheaper to use a temporary dict and do the update. For large dicts (on the defaults side), it may make more sense to reduce the number of objects that need to be created:

   target = ...
   has_key = target.has_key
   for key in defaults.keys():
       if not has_key(key):
           target[key] = defaults[key]

This saves the construction of len(defaults) 2-tuples.

-Fred

-- Fred L. Drake, Jr. Corporation for National Research Initiatives