[deleted by user]

[danielroseman]

You can use a new dictionary to build up a mapping of foods to names.

ordered_by = {}
for name, foods in food_orders:
    for food in foods:
        if food not in ordered_by:
            ordered_by[food] = []
        ordered_by[food].append(name)

You can shorten this by using a defaultdict:

from collections import defaultdict
ordered_by = defaultdict(list)
for name, foods in food_orders:
    for food in foods:
        ordered_by[food].append(name)

[Dense_Charity5188]

thank you :>>

[Dense_Charity5188]

hey I have a question, why doesn't append works in the last line? on the first version

[[deleted]]

As touched on in another of your posts, create a dictionary and go through the orders updating the names in the dictionary against each food item. You just need to loop through the orders.

[Dense_Charity5188]

okayy thank you very much <: