"Michele Petrazzo" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> > when we expect that the key will most often be in my_dict so that
> > exception will be raised rarely
>
> I didn't thought this because if I think that a key aren't in a dict, I
> use dict.get(key, default)
>
Another factor to consider is if "default" is not something simple like 0 or
None, but is an object constructed and initialized with some expensive
initialization code (like access to a database). In this case:
dict.get(key, ExpensiveObjectToCreate())
always creates the default value, and if the key does not exist, then
promptly drops it on the floor.
In such a case you'd be better off with one of the "check for existence"
patterns, which only creates the default value if you *know* you're going to
need it.
-- Paul
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