The "coding" here is a bytes-to-text encoding. The Python lexer expects to see character data; you get to insert arbitrary code to convert the bytes to characters (or just use existing schemes the implement standards like UTF-8).
new_dict = {**old_dict, **update_keys_and_values_dict}
new_dict = {
**old_dict,
**{
key: val
for key, val in update_keys_and_values_dict
if key not in some_other_dict
}
}
new_dict = old_dict | update_keys_and_values_dict the_dict |= update_keys_and_values_dictAnd like += over list.extend, |= over dict.update is very little gain, and restricts legal locations (augmented assignments are statements, method calls are expressions even if they return "nothing")
dct = {'a': [1, 2, 3]}
{'a': [1, *rest]} = dct
print(rest) # [2, 3]
dct = {'a': [1, 2, 3]}
{'b': [4, *rest]} = dct
print(rest) # [2, 3]
dct = {'a': [1, 2, 3]}
{'_': [_, *rest]} = dct
print(rest) # [2, 3]You can't land a language feature that only sometimes works - that's absolutely horrid UX.
> can't we just copy whatever JS does?
I wasn't aware that js does this and I don't know it's implemented. So maybe I should retract my claim about compiler assistance.
def u(**kwargs):
return tuple(kwargs.values())
*I realize the tuple can be omitted here
>>> def u(locals, dct, keys):
... for k in keys:
... locals[k] = dct[k]
...
>>> dct = {'greeting': 'hello', 'thing': 'world', 'farewell': 'bye'}
>>> u(locals(), dct, ['greeting', 'thing'])
>>> greeting
'hello'
>>> thing
'world'
>>> farewell
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'farewell' is not defined
>>> from operator import itemgetter
>>> dct = {'greeting': 'hello', 'thing': 'world', 'farewell': 'bye'}
>>> thing, greeting = itemgetter("thing", "greeting")(dct)
>>> thing
'world'
>>> greeting
'hello'