CODEWITHSUNDEEP
python
sunny
sunny

Reputation: 3891

How to change list of objects into list of dicts?

I am quite surprised at the behavior of this code, which is inside a function:

        for user in full_details["users"]:
            user = collections.defaultdict(lambda: False, user)
            if user["comments"]:
                user["comments"] = [comment.__dict__ for comment in user["comments"]]
                print("just converted user comments to dict objects")
                print(user["comments"])


        print("printing full details")
        print(full_details)

My understanding was that if I modified a dictionary or a list, that modification applied to the object and would remain. However, when I change user["comments"] for each user in full_details["users"] within my if I am not then seeing those same changes again reflected in full_details just immediately after. Why is that? I thought that whenever you create a new list and assign it to a passed-in parameter, that new list will persist outside the function.

My trouble is that the change made here does not persist:

                user["comments"] = [comment.__dict__ for comment in user["comments"]]

Also, full_details is a default_dict: 

full_details = collections.defaultdict(lambda: False, thread_details.__dict__)

Upvotes: 0

Views: 86

Answers (1)

RobertB
RobertB

Reputation: 1929

You are assigning "user" twice. First in the for statement. Then in the first line of the body of the for loop, you are creating a new object and also assigning it to "user". At this point, you have lost your reference to the original object.

Upvotes: 1

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