On 05/25/2016 12:38 PM, Sven R. Kunze wrote:
On 25.05.2016 20:42, Steven D'Aprano wrote:
There's no need to unpack the entire dict, you can grab only the keys you need:
width, height = **prefs
# like width = prefs['width'] height = prefs['height']
That's not the same behavior as it is for tuple unpacking. As a new user, I would expect them to work the same way.
If I want to dismiss the remainder of the dict, I'd rather consider an explicit approach:
width, height = **prefs # just those values width, height, *r = **prefs # r captures the rest
This gives me two benefits:
1) I can further work with r from which width and height are extracted 2) a convenient way of verifying that a dict only contains certain values and extracting those at the same time
Okay, those are good benefits. +1
Maybe, it's just me but I still tend to think that using unquoted strings should be reserved for attribute unpacking.
lists, tuples, and dicts are basic containers -- having syntax to unpacak them easily is a clear win; attribute unpacking not so much: --> some_long_object_name = MyClass(blah, blah) --> s = some_long_object_name --> s.name some value --> s.value --> another value which is sufficiently readable.
One additional drawback of this solution is the fact that the "value" part of the colon is already taken. So, value matching like done in Erlang is not possible. OTOH, this applies to tuple unpacking in its current form as well
This is about unpacking, not matching. -- ~Ethan~