Question

Can this Python code be shortened and still be readable using itertools and sets?

result = {}
for widget_type, app in widgets:
    if widget_type not in result:
        result[widget_type] = []
    result[widget_type].append(app)

I can think of this only:

widget_types = zip(*widgets)[0]
dict([k, [v for w, v in widgets if w == k]) for k in set(widget_types)])

Answer 1

You can use a defaultdict(list).

from collections import defaultdict

result = defaultdict(list)
for widget_type, app in widgets:
    result[widget_type].append(app)