A syntax that would work (which atm is a syntax error, and requires no new keyword) would be

    student_by_school = {school: [student] for school, student in student_school_list, grouped=True}

with grouped=True being a modifier on the dict comprehension so that at each iteration loop

current_dict[key] = value if key not in current_dict else current_dict[key] + value

This is an extremely borderline syntax (as it is perfectly legal to put **{'grouped': True} in a dict comprehension), but it works.
It even keeps the extremely important "should look like a template of the final object" property.

But it doesn't requires me to defines 2 lambda functions just to do the job of a comprehension.

Nicolas Rolin

2018-06-29 4:57 GMT+02:00 Michael Selik <mike@selik.org>:
On Thu, Jun 28, 2018, 6:46 PM Nicolas Rolin <nicolas.rolin@tiime.fr> wrote:
The questions I should have asked In my original post was :
- Is splitting lists into sublists (by grouping elements) a high level enough construction to be worthy of a nice integration in the comprehension syntax ?

My intuition is no, it's not important enough to alter the syntax, despite being an important task.

- In which case, is there a way to find a simple syntax that is not too confusing ?

If you'd like to give it a shot, try to find something which is currently invalid syntax, but does not break compatibility. The latter criteria means no new keywords. The syntax should look nice as a single line with reasonably verbose variable names.

One issue is that Python code is mostly 1-dimensional, characters in a line, and you're trying to express something which is 2-dimensional, in a sense. There's only so much you can do without newlines and indentation.


Nicolas Rolin
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