On Thu, Oct 14, 2021 at 12:32:57AM +0400, Abdulla Al Kathiri wrote:
> Today I found myself write a function that returns a tuple of list of
> list of strings (tuple[list[list[str]], list[list[str]]]). Wouldn’t it
> easier to read to write it like the following:
> ([[str]], [[str]])?
Not really. Your first example is explicit and I can get the meaning by
just reading it out loud:
tuple[list[list[str]], list[list[str]]]
"tuple (of) list (of) list (of) str, list (of) list (of) str
Your abbreviated version:
([[str]], [[str]])
is too terse. I have to stop and think about what it means, not just
read it out loud. Without the hint of named types (tuple and list), my
first reaction to seeing [str] is "is this an optional string?".
And then I wonder why it's not written:
([[""]], [[""]])
Why abbreviate list and tuple but not string?
Code is read more than it is written, and can be too terse as well as
too verbose.
On the other hand:
> Similarly for TypedDict, replace the following..
> class Movie(TypedDict):
> name: str
> year: int
> with
> {‘name’: str, ‘year’: int}
To my eye, that one does work. As far as I know, curly brackets {}
aren't otherwise used in annotations (unlike square brackets), and they
don't look like "optional" to me. They look like a dict.
So on first glance at least, I think that:
{'name': str, 'year': int}
is better than the class syntax we already have.
Likewise:
> dict[str, int] will be {str: int}
> set[int] will be {int}.
work for me too.
> Also, Annotated[float, “seconds”] can be replaced with something like
> float #seconds indicating whatever comes after the hashtag is just
> extra information similar to a normal comment in the code.
No, because the # indicates that the rest of the line is a comment. This
is already legal:
def func(d: {str # this is an actual comment
: int}) -> Any: ...
so this would be ambiguous between a real comment and an annotation.
Even if we agreed to change the behaviour of comments, you suggested:
func(d: {str # product label: [float] # prices from 2000 to 2015})
How is the interpreter to know that the first annotation is just
"product label"
rather than this?
"product label: [float] # prices from 2000 to 2015"
So I don't think this works.
--
Steve
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