JSON - Generating a json in a loop in python

Question

I have some difficulties generating a specific JSON object in python.

I need it to be in this format:

[
   {"id":0 , "attributeName_1":"value" , "attributeName_2":"value" , .... },
   {"id":1 , "attributeName_2":"value" , "attributeName_3":"value" , .... },
   .
   .
   .
]

In python, im getting the ids, attributeNames and values from 2 objects. Im trying to generate the json like this:

    data=[]
    for feature in features_selected:
        data.append({"id":feature.pk})
        for attribute in attributes_selected:
            if attribute.feature == feature:
                data.append({attribute.attribute.name : attribute.value})
        jsonData=json.dumps(data)

but I got this result which is not exactly what I need:

[
   {"id":0} , {"attributeName_1":"value"} , {"attributeName_2":"value"} ,
   {"id":1} , {"attributeName_2":"value"} , {"attributeName_3":"value"} , .... },
   .
   .
   .
]

Answer 1

The problem is that you are appending to data multiple times in the loop: first {"id":feature.pk}, then {attribute.attribute.name : attribute.value} in the inner loop.

Instead, you need to define a dictionary inside the loop, fill it with id item and attributes and only then append:

data=[]
for feature in features_selected:
    item = {"id": feature.pk}
    for attribute in attributes_selected:
        if attribute.feature == feature:
            item[attribute.attribute.name] = attribute.value
    data.append(item)

jsonData=json.dumps(data)