How do I combine several dictionaries with the same keys without losing any of values?

I have a list with several dicts:

l = [{'a': 'a1'}, {'c': 'c'}, {'a': 'a2'}, {'a': 'a3'}, {'y': 'y1'}, {'y': 'y4'}  etc]

and I want to combine them so that I’d get something like this:

l2 = [{'a': 'a1', 'a2', 'a3'}, {'c': 'c'}, {'y': 'y1', 'y4'}  etc]

How can I do this?

I tried to merge them but I ended up losing some of values every time.

>Solution :

Try this:

from collections import defaultdict

l = [{'a': 'a1'}, {'c': 'c'}, {'a': 'a2'}, {'a': 'a3'}, {'y': 'y1'}, {'y': 'y4'}]

merged_dict = defaultdict(list)

for d in l:
    for key, value in d.items():
        merged_dict[key].append(value)

result = [{key: values} for key, values in merged_dict.items()]

print(result)

OUTPUT

[{'a': ['a1', 'a2', 'a3']}, {'c': ['c']}, {'y': ['y1', 'y4']}]