Need to get an average of a dictionary Key from a JSON file-CodePudding

I have a JSON file with this format:

{
    "people":    [
        {
            "name": "John Smith",
            "age":19,
            "member": false
        },
        {
            "name": "John Doe",
            "age": 23,
            "member": false
        },
        {
            "name": "Michael Johnson",
            "age":19,
            "member": false
        },
        {
            "name": "Daniel Katz",
            "age":17,
            "member": false
        }
    ]
}

I need to load it as a Python object and calculate the age average. However, any For loop I tried running on this file after opening the file resulted in some sort of TypeError. Any suggestions on how to perform this?

import json
with open('students.json') as f:
    data = json.load(f)
    data_people = data['people']

CodePudding user response：

You can use statistics.mean on your dictionary:

import json
from statistics import mean

with open('students.json') as f:
    data = json.load(f)

avg_age = mean(p['age'] for p in data['people'])

output: 19.5

CodePudding user response：

I've run your code and it works fine for me. My Python version is 3.10.2 and my OS is win11. Would you like to elaborate your error message?

CodePudding user response：

get list of peoples and use sum on its age key:

import json


text = """{
    "people":    [
        {
            "name": "John Smith",
            "age": 19,
            "member": false
        },
        {
            "name": "John Doe",
            "age": 23,
            "member": false
        },
        {
            "name": "Michael Johnson",
            "age": 19,
            "member": false
        },
        {
            "name": "Daniel Katz",
            "age": 17,
            "member": false
        }
    ]
}"""

data = json.loads(text)
# or
# with open('students.json') as f:
#    data = json.load(f)


average = lambda l: sum(map(lambda x: x["age"], l ))/ len(l)
print(average(data["people"]))

output: 19.5