Issue in iterating over Python dictionaries with lists and sub-dictionaries

February 26, 2024

I have a data structure I have read from a file which looks like below –

data = {"test":['[{"Day":"Monday","Device":"Android","Data":[1, 2, 3]}, {"Day":"Tuesday","Device":"Iphone","Data":[10, 20, 30]}]']}

I am trying to access the elements of the structure like below, peeling off one by one –

value = data["test"]
print(value)
#['[{"Day":"Monday","Device":"Android","Data":[1, 2, 3]}, {"Day":"Tuesday","Device":"Iphone","Data":[10, 20, 30]}]']

value1 = value[0]
print(value1)
#[{"Day":"Monday","Device":"Android","Data":[1, 2, 3]}, {"Day":"Tuesday","Device":"Iphone","Data":[10, 20, 30]}]


print(value1[0]) 
#I get only [ as if it is a string

Does the incoming structure has some problems, or am I accessing the wrong way.

Here is the link to reproduce – https://godbolt.org/

>Solution :

You can use the built-in JSON parser to convert this to a dictionary like so:

import json

for item in json.loads(data['test'][0]):
    print(item, type(item))

# >>> {'Day': 'Monday', 'Device': 'Android', 'Data': [1, 2, 3]} <class 'dict'>
# >>> {'Day': 'Tuesday', 'Device': 'Iphone', 'Data': [10, 20, 30]} <class 'dict'>

Note: printing type(item) is just to demonstrate that they’re being converted to dict appropriately