Error when trying to get len() from json object

Question

When I'm trying to get the length of a json object I'm getting the following error:
size = len(response_info[weapon]['traitIds']) KeyError: 'traitIds' I get no error when removing the len() and the object is looks like the following:
traitIds:['value1', 'value2']
Do you know how I can fix this?

I'm using the following json file: https://www.bungie.net/common/destiny2_content/json/en/DestinyInventoryItemDefinition-33183ba8-e1c4-4364-8827-dbdcf46315dd.json

Code Sample:

for weapon in response_info:
    size = len(response_info[weapon]['traitIds'])
    if (i <= i):
        while x <= size:
            try:
                if (response_info[weapon]['traitIds'][x] == 'item_type.weapon'):
                
                    print(response_info[weapon]['displayProperties']['name'])
                    i += 1
                    print(size)
            except:
                pass
            x += 1

Answer 1

there are items without traitIds, so you need to handle this case.

import requests

url = 'https://www.bungie.net/common/destiny2_content/json/en/DestinyInventoryItemDefinition-33183ba8-e1c4-4364-8827-dbdcf46315dd.json'
resp = requests.get(url)
data = resp.json()

for key, value in data.items():
    trait_ids = value.get('traitIds') # this will yield None if traitIds key is missing
    if trait_ids and 'item_type.weapon' in trait_ids:
        print(value['displayProperties']['name']) # you may want to use .get() also here to avoid possible KeyError.