How to merge the list in `defaultdict` using keys, but keep the list separate within that key?

Question

I want to merge the list in defaultdict which has class (keys) and list-values from two different data/file. I want to merge the list using the unique key but keep the list values separate.

Input:

defaultdict(<class 'list'>, {'1335': ['C', 'T', 'T', 'C', 'T', 'G'], '254': ['T', 'T', 'G', 'C', 'G', 'G']})

defaultdict(<class 'list'>, {'1335': ['A', 'C', 'A', 'A', 'C', 'A'], '254': ['A', 'G', 'A', 'T', 'A', 'A']})

output:

defaultdict(<class 'list'>, {'1335': ['C', 'T', 'T', 'C', 'T', 'G'], ['A', 'C', 'A', 'A', 'C', 'A'] , '254': ['T', 'T', 'G', 'C', 'G', 'G'], ['A', 'G', 'A', 'T', 'A', 'A']})

Thanks,

Answer 1

You want the new dictionary's value to be a list of lists.

You can create a new defaultdict of lists, and append the list value from each dictionary:

input_dicts = [dict1, dict2]

result = defaultdict(list)

for to_merge in input_dicts:
    for key, value in to_merge.items():
        result[key].append(value)