I'm using Python 3.8. If I want to get a unique set of values for an array of dictionaries, I can do the below
>>> lis = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
>>> s = set( val for dic in lis for val in dic.values())
>>> s
{1, 2, 3, 4}
However, how would I refine the above if I only wanted a unique set of values for the dictionary key "a"? In the above, the answer would be
{1, 3}
I'll assume that each dictionary in the array has the same set of keys.
You could simply do:
lis = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
# assuming the variable key points to what you want
key = 'a'
a_values = set(dictionary[key] for dictionary in lis)
I hope I've understood what you are looking for. Thanks.
You can do it like this:
lis = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
search_key = 'a'
s = set(val for dic in lis for key, val in dic.items() if key == search_key)
print(s)
#OUTPUT: {1, 3}
Use the dic.items() instead of dic.values() and check where the key is a.
Another way to do it to simplify the things:
lis = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
search_key = 'a'
s = set(dic.get(search_key) for dic in lis)
print(s)
