使用列表作为python中的值在字典中搜索特定列表

Question

I have a dictionary with strings as keys and lists as values. I now have another list (list2) and I would like to search if there are any dictionary values lists that contain all the items of list2. I would then like the output to be the key of the matching dictionary value list.

My code now looks something like this:

for elem in list2:
    for elem2 in dict.keys():
        if all(item in elem2 foritem in list2):
            print(elem2)

value_found_list = dict.get(elem2)

print(value_found_list)

Edit minimal reproducable example:

dict{
"key1": ['item1', 'item2', 'item3'], 
"key2": ['item2', 'item4', 'item5'],
"key3": ['item3', 'item6', 'item4']
}
list = ['item2', 'item3']

How would I with this data return which dictionary key contains all items in the list?

Answer 1

You're better off changing your second list to a set if you're planning on doing membership checking.

Here's a short function that does just that.

Edit: Since you're doing it the other way around it's probably less time intensive to just use the list in your dict . However, It may make more sense to have them in the form of a set in the first place. A set is hashed which translates to faster lookup time. If your list s are pretty long, you'll save some computation time by having them in this form.

def get_key(dct, lst2):
    # iterate through every key and list
    for key, lst in dct.items():
        # if all the list items are present in your second list
        if all(i in lst for i in lst2):
            return key
    # default to returning None
    return None

dct = {
"key1": ['item1', 'item2', 'item3'], 
"key2": ['item2', 'item4', 'item5'],
"key3": ['item3', 'item6', 'item4']
}
lst = ['item2', 'item3']
print(get_key(dct, lst))

Where you were going wrong is here.

    for elem2 in dict.keys():
        if all(item in elem2 foritem in list2):

elem2 is a string key. item in elem2 is looking for the full string within the key. dict.values() returns the values or lists that you were probably looking for.

However dict.items() returns the keys and values as a tuple which is probably what you need.

Answer 2

Watch this

a = {'one':[1, 2, 3, 4], 'two':[5, 6, 7, 8], 'three':[9, 10]}
b = {'four':[1, 2, 3, 4], 'five':[6, 7, 8], 'six':[9, 10]}
for akey in a:
    for bkey in b:
        if a[akey] == b[bkey]:
            print(akey, bkey)

outputs:

one four
three six

Answer 3

l=[i for i in your_dict if set(your_dict[i]).union(set(list2))==set(your_dict[i])]

print(l)

for:

your_dict={
"key1": ['item1', 'item2', 'item3'], 
"key2": ['item2', 'item4', 'item5'],
"key3": ['item3', 'item6', 'item4']
}
list2 = ['item2', 'item3']

The output is:

['key1']