On 04/10/2019 20:34, Caleb Donovick wrote:
While there is no restriction on passing dicts to getitem. Doing so tends to be a bit ugly. I have two main use cases in mind for this syntax.
The first and perhaps the most obvious, is doing relational queries.
where_x_1 = db[x=1]is more beautiful than
where_x_1 = db[dict(x=1)] where_x_1 = db[{'x': 1}] # or by abusing slices where_x_1 = db['x':1] # or in the style of Pandas where_x_1 = db[db['x'] == 1]
OK, I'm not sure what you're trying to do here, which all on its own says that what you're doing isn't self-explanatory. Would I be right in thinking you want a shorthand for:
where_x_1 = [k for k,v in db if v == 1]
If so, I'd rather the comprehension, thanks. It at least says what it does.
Beyond relational queries my own personal use case is a shorthand for dataclasses / protocols.
foo: ProtoRecord[x=int, y=int] = DataRecord[x=int, y=int](0, 1)where `DataRecord[field0=T0, ..., fieldk=Tk]` generates
@dataclass class Record: field0: T0 ... fieldk: Tkand `ProtoRecord[field0=T0, ..., fieldk=Tk]` generates a similar protocol.
Explicit is better than implicit.
Allowing key value pairs in geitem need not change the interface of getitem. All the key value pairs could be collected as a dict and passed to getitem as the index.
Um. Stop me if I'm wrong, but isn't that exactly a change to the interface of getitem?
Sorry, I don't like it.