remove keys in a dictionary if a value in its dictionary field is a subset

Question

I need to get the cat_n with maximum matches and remove cat_m if it is a subset. For example

vehicle_dict = {"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "auto"]}}

should return

{"cat_1":{"type":["car", "bus", "auto"]}}

but

vehicle_dict = {"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "train"]}}

should return both i.e

{"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "train"]}} as none of them are a subset.

So for

vehicle_dict = {"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "auto"]}, "cat_3": {"type":["car", "train"]}}

it should return

{"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "train"]}}

Answer 1

I assume that the goal is to filter the vehicle_dict as follows: For each category cat_x in sequence, exclude the category if all its types have already been seen in previous categories.

The code:

def filter(vehicle_dict):
    result = {}
    all = set()  # Set of all types types encountered so far
    i = 0  # Categoey number in the result
    for cat in sorted(vehicle_dict.keys()):
        types = vehicle_dict[cat]['type']  # Get the category types
        typeset = set(types)  # Make a set out of the types,
        # If and only if the category contains new type(s) it is included in the result
        if not typeset.issubset(all):
            i += 1
            result[f'cat_{i}'] = vehicle_dict[cat]  # Include the category in the resul
t
            all = all.union(typeset)  # Keep track of all types encountered so far.
    return result

vehicle_dict = {"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "auto"]}}
print(filter(vehicle_dict))

vehicle_dict = {"cat_1":{"type":["car", "bus", "auto"]}, "cat_2": {"type":["car", "auto"]}, "cat_3": {"type":["car", "train"]}}
print(filter(vehicle_dict))

Output

{'cat_1': {'type': ['car', 'bus', 'auto']}}
{'cat_1': {'type': ['car', 'bus', 'auto']}, 'cat_2': {'type': ['car', 'train']}}