Remove object if empty list inside it in Python

Question

I have a json file with objects with the same ID. I have a results list inside each. How to remove the entire object if results == [] ? I have a And I have a UnboundLocalError: local variable 'item' referenced before assignment error.

JSON input:

[{
    "objectID": 10745,
    "results": [
    {
        "model": "AUDI - TT QUATTRO",
        "price_str": "4 800 €"
        }]
    },
 {
    "objectID": 10745,
    "results": []
    }
]

My code:

for item in data:
    objectId = item["objectID"]
    results = item["results"]

    def removeDuplicate():
        if not results:
            del item
    removeDuplicate()

The expected output:

[{
    "objectID": 10745,
    "results": [
    {
        "model": "AUDI - TT QUATTRO",
        "price_str": "4 800 €"
         }]
    }
]

Read [short-description-of-the-scoping-rules](https://stackoverflow.com/questions/291978/short-description-of-the-scoping-rules) to get the error message. — Patrick Artner, Apr 30 '20 at 15:20

score 2 · Accepted Answer · answered Apr 30 '20 at 15:24

2

Deleting items from a list while iterating the same list is likely to cause trouble. Try constructing a new list instead with filtering logic to remove the unwanted items:

new_data = [item for item in data if item['results']]

answered Apr 30 '20 at 15:24

AbbeGijly

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5

score 0 · Answer 2 · answered Apr 30 '20 at 15:23

Filter on the list of dictionaries based on the dicts value for "results":

data = [{
    "objectID": 10745,
    "results": [
    {
        "model": "AUDI - TT QUATTRO",
        "price_str": "4 800 EUR"
    }]
    },
    {
    "objectID": 10745,
    "results": []
    }
]

cleared = [i for i in data if i.get("results")] 

print(cleared)

Output:

[{'objectID': 10745, 
  'results': [{'model': 'AUDI - TT QUATTRO', 'price_str': '4 800 EUR'}]}]

If no "results"in the dict .get() will return None - if present and empty it is falsy as well (None and empty lists are) and it will not land inside cleared.

Regarding your error a good read of short-description-of-the-scoping-rules should help you get the error message: your item is not declared inside your functions scope and python does not allow you to use the item from the for loop.

Remove object if empty list inside it in Python

2 Answers2

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