从字典列表创建新字典

Question

I have a list of dictionaries, that looks like this:

my_dicts = 
[{'1A': 1, '3E': 2, 'PRODUCT NAME': 'White Bread loaf large', 'Week': 1},
 {'1A': 1, '1B': 1, '1C': 1, '1D': 2, '1E': 2, '2C': 1, '3E': 2, 'PRODUCT NAME': 'Brown Bread loaf 
 large', 'Week': 1}...]

I want to create a new dictionary, that looks like this:

new_dict = 
[{'HOUSE NAME': '1A', 'White Bread Loaf Large' : 1, 'Brown Bread loaf large' : 1},
 {'HOUSE NAME': '1B', 'Brown Bread loaf large' : 1},...
 {'HOUSE NAME': '3E', 'White Bread Loaf Large' : 2, 'Brown Bread Loaf Large' : 2}]

Each 'HOUSE NAME' is unique.

I have a solution, that creates the new dictionary, and works with the sample list I've provided, but it does not work for my actual list (that contains 27 dictionaries)

This is the solution:

houses = set(['1A', '1B', '1C', '1D', '3E'])

output_list = []

for house in houses:
    output_entry = {}
    output_entry["HOUSE NAME"] = house
    for entry in my_dicts:
        if entry.get(house) and entry.get("PRODUCT NAME"):
            product_name = entry.get("PRODUCT NAME")
            if output_entry.get(product_name):
                output_entry[product_name] += 1
            else:
                output_entry[product_name] = 1

    output_list.append(output_entry)

The solution's last if statement doesnt seem to work, as whatever I set the 'else's condition to, is what my values are set to.

Answer 1

You could do it like this:

my_dicts = [{'1A': 1, '3E': 2, 
             'PRODUCT NAME': 'White Bread loaf large', 'Week': 1},
            {'1A': 1, '1B': 1, '1C': 1, '1D': 2, '1E': 2, '2C': 1, '3E': 2,
             'PRODUCT NAME': 'Brown Bread loaf large', 'Week': 1}]

merged = dict()
for d in my_dicts:
    for k,v in d.items():
        if k in ('PRODUCT NAME','Week'): continue # only process house names
        merged.setdefault(k,{'HOUSE NAME':k}).update({d['PRODUCT NAME']:v})
result = list(merged.values())

print(result)

[{'HOUSE NAME': '1A', 'White Bread loaf large': 1, 'Brown Bread loaf large': 1},
 {'HOUSE NAME': '3E', 'White Bread loaf large': 2, 'Brown Bread loaf large': 2},
 {'HOUSE NAME': '1B', 'Brown Bread loaf large': 1},
 {'HOUSE NAME': '1C', 'Brown Bread loaf large': 1},
 {'HOUSE NAME': '1D', 'Brown Bread loaf large': 2},
 {'HOUSE NAME': '1E', 'Brown Bread loaf large': 2},
 {'HOUSE NAME': '2C', 'Brown Bread loaf large': 1}]

The merged dictionary serves as a temporary index to assemble the new list of dictionaries by updating them based on each house name. Then the final result is obtained by ignoring the indexing par of merged , only taking the values (ie dictionaries merged by house)