获取 json python 中每个键的平均值

Question

Suppose I have a json array like this:

[{'Time':'09:30', 'Price':'5.49'}, {'Time':'09:31', 'Price':'5.59'}, {'Time':'09:32', 'Price':'5.39'}, {'Time':'09:30', 'Price':'8.49'}, {'Time':'09:31', 'Price':'7.49'}, {'Time':'09:32', 'Price':'10.49'}]

How would I create a new json array where the json contains no duplicates of time, and an average of each price within the same key?

Something like this is what I am talking about:

[{'Time':'09:30', 'Price':'6.99'}, {'Time':'09:31', 'Price':'6.54'}, {'Time':'09:32', 'Price':'7.94'}]

This is what i have tries so far:

def stack_overflow(self, json_price_action):
    average = []
    for i, json in enumerate(json_price_action):
        average.append({
            'Time': json['Time'],
            'Price': json['Price'],
            'Count': 0
        })
        for index, avg_json in enumerate(average):
            
            if average[index]['Time'] == json['Time']:
                average[index]['Price'] += json['Price']
                average[index]['Count'] += 1
            
    print(average)

I tried to make a counter so I can divide the sum of each timefram by counter. However, I get duplicate time values.

Answer 1

You can use a defaultdict to grab all the values while making sure not to have duplicates and average out all values with a dict comprehension.

from collections import defaultdict
from statistics import mean

data = [
    {"Time": "09:30", "Price": "5.49"},
    {"Time": "09:31", "Price": "5.59"},
    {"Time": "09:32", "Price": "5.39"},
    {"Time": "09:30", "Price": "8.49"},
    {"Time": "09:31", "Price": "7.49"},
    {"Time": "09:32", "Price": "10.49"},
]

res = defaultdict(list)
for i in data:
    res[i["Time"]].append(float(i["Price"]))

res = {k: mean(v) for k, v in res.items()}

print(res)
# {'09:30': 6.99, '09:31': 6.54, '09:32': 7.9399999999999995}