I have 2 lists, I want to merge them, answer should be like below

Question

I have two lists of dictionaries and I'd like to merge them. When a dictionary is present in both lists, I'd like to add a "confidence" key to the dictionary to reflect that the dictionary was present in both lists.

List-1

lst1 = [
    {'key': 'data_collected.service_data'},
    {'key': 'gdpr.gdpr_compliance'},
    {'key': 'disclosure_of_information.purpose_of_disclosure'},
    {'key': 'opt_out.choice_of_opt_out'}
]

List-2

lst2 = [
    {'key': 'child_data_protection.parent_guardian_consent'},
    {'key': 'ccpa.ccpa_compliance'},
    {'key': 'disclosure_of_information.purpose_of_disclosure'},
    {'key': 'opt_out.choice_of_opt_out'}
]

when i run below code i am not getting proper output

res = []
for x in lst1:
    for y in lst2:
        if x["key"] == y["key"]:
            if x not in res and y not in res:
                res.append({"key": x["key"], "confidence": 1})
        else:
            if x not in res and y not in res:
                res.append(x)
                res.append(y)

print(res)

OUTPUT should like

[
    {'key': 'data_collected.service_data'},
    {'key': 'gdpr.gdpr_compliance'},
    {
        'key': 'disclosure_of_information.purpose_of_disclosure',
        'confidence': 1
    },
    {
        'key': 'opt_out.choice_of_opt_out',
        'confidence': 1
    },
    {'key': 'child_data_protection.parent_guardian_consent'},
    {'key': 'ccpa.ccpa_compliance'}
]

Answer 1

Another approach can be:

lst1 = [
    {'key': 'data_collected.service_data'},
    {'key': 'gdpr.gdpr_compliance'},
    {'key': 'disclosure_of_information.purpose_of_disclosure'},
    {'key': 'opt_out.choice_of_opt_out'}
]
lst2 = [
    {'key': 'child_data_protection.parent_guardian_consent'},
    {'key': 'ccpa.ccpa_compliance'},
    {'key': 'disclosure_of_information.purpose_of_disclosure'},
    {'key': 'opt_out.choice_of_opt_out'}
]
for data in lst1:
    # If same data exists in lst2, add confidence key and remove it from lst2
    if data in lst2:
        lst2.remove(data)
        data['confidence']=1

# At the end of above for loop, lst2 contains unique data, now just add both the lists to get the final result            
lst1 = lst1+lst2        
print (lst1)

Output:

[{'key': 'data_collected.service_data'}, {'key': 'gdpr.gdpr_compliance'}, {'key': 'disclosure_of_information.purpose_of_disclosure', 'confidence': 1}, {'key': 'opt_out.choice_of_opt_out', 'confidence': 1}, {'key': 'child_data_protection.parent_guardian_consent'}, {'key': 'ccpa.ccpa_compliance'}]