[del]eting an item from a JSON dictionary leaves an empty dict: `{}`. How do I remove it completely?

Question

I am trying to delete a dictionary item nested within a list, in a dict.
After I del the object, the modified dictionary will contain an empty dictionary: {} in the place of the deleted object.
Here is the code I am using:

json_dict = {"top_key": "top_value", "bottom_key": [{"list_dict": "list_dict_value"},{"list_dict1": "list_dict_value1"}]}

print("initial:", json_dict)

def delete(list_dict):
    for i in json_dict["bottom_key"]:
        if list_dict in i:
            del i[list_dict]


delete("list_dict")
print("final:", json_dict)  

The final print will return:
final: {'bottom_key': [{}, {'list_dict1': 'list_dict_value1'}], 'top_key': 'top_value'} (pw-retriever) simon@[pw-retriever](fix_del_ls)

I am trying to find a way to remove the {} in addition to the key:value pair, in one go.

edit: an explanation as to what the heck is going on would also be highly appreciated.

Answer 1

You can do the following:

for i in json_dict["bottom_key"][:]:  # important: iterate a shallow copy
    if list_dict in i:
        json_dict["bottom_key"].remove(i)

However, since removing from a list is O(N) and you might have to remove multiple elements, you might consider just rebuilding it from scratch in one go:

json_dict["bottom_key"] = [d for d in json_dict["bottom_key"] if list_dict not in d]

Answer 2

Constructing further on basis of your structure, del using the index of the dict , like follows :

def delete(list_dict):
    for i,ele in enumerate(json_dict["bottom_key"][:]) :
        if list_dict in ele:
            del json_dict["bottom_key"][i]

#driver values :

IN : initial: {'top_key': 'top_value', 'bottom_key': [{'list_dict': 'list_dict_value'}, {'list_dict1': 'list_dict_value1'}]}

>>> delete("list_dict")

OUT : final: {'top_key': 'top_value', 'bottom_key': [{'list_dict1': 'list_dict_value1'}]}

EDIT : schwobaseggl's idea of reconstructing the dictionary is better than deleting the elements as the previous one can lead to logical mistakes.