Sum up how many fields are empty or do not exist in a dict-CodePudding

I have a problem. I have a list myList inside these list, there a dictonaries. I want to count if the field dataOriginSystem is empty or does not exist. Unfortunately I got the wrong result. if(key_nested == 'dataOriginSystem'): ... else: count = 1

The reason for this lies in the if-query. Since I am asking, does the field exist? If no, then count it up and since I loop through all the nested keys, one of the errors is here. Also, is there a way to make this more efficient?

How can I query how many of the field dataOriginSystem are empty or non-existent?

count = 0
for element in myList:
    for key in element.keys():
        if(key == 'metaData'):
            for key_nested in element[key].keys(): 
                if(key_nested == 'dataOriginSystem'):
                    if(key_nested == None):
                        count  = 1
                else:
                    count  = 1
print(count)

myList = [
{'_id': 'orders/213123',
 'contactEditor': {'name': 'Max Power',
  'phone': '1234567',
  'email': '[email protected]'},
 'contactSoldToParty': {'name': 'Max Not',
  'phone': '123456789',
  'email': '[email protected]'},
 'isCompleteDelivery': False,
 'metaData': {'dataOriginSystem': 'Goods',
  'dataOriginWasCreatedTime': '10:12:12',},
 'orderDate': '2021-02-22',
 'orderDateBuyer': '2021-02-22',
},
{'_id': 'orders/12323',
 'contactEditor': {'name': 'Max Power2',
  'phone': '1234567',
  'email': '[email protected]'},
 'contactSoldToParty': {'name': 'Max Not',
  'phone': '123456789',
  'email': '[email protected]'},
 'isCompleteDelivery': False,
 'metaData': {'dataOriginSystem': 'Goods',
  'dataOriginWasCreatedTime': '10:12:12',},
 'orderDate': '2021-02-22',
 'orderDateBuyer': '2021-02-22',
 },
{'_id': 'orders/12323',
 'contactEditor': {'name': 'Max Power2',
  'phone': '1234567',
  'email': '[email protected]'},
 'contactSoldToParty': {'name': 'Max Not',
  'phone': '123456789',
  'email': '[email protected]'},
 'isCompleteDelivery': False,
 'metaData': {
  'dataOriginWasCreatedTime': '10:12:12',},
 'orderDate': '2021-02-22',
 'orderDateBuyer': '2021-02-22',
 },
{'_id': 'orders/12323',
 'contactEditor': {'name': 'Max Power2',
  'phone': '1234567',
  'email': '[email protected]'},
 'contactSoldToParty': {'name': 'Max Not',
  'phone': '123456789',
  'email': '[email protected]'},
 'isCompleteDelivery': False,
 'metaData': {'dataOriginSystem': None,
  'dataOriginWasCreatedTime': '10:12:12',},
 'orderDate': '2021-02-22',
 'orderDateBuyer': '2021-02-22',
 },
]

Result should be

[OUT] 2
# Because of the two last elements.
# The first element does not exist
# and the second ist None.

CodePudding user response：

You can use dict.get directly on the nested key, returning a default value of None, and then count the number of None values you get:

sum(d['metaData'].get('dataOriginSystem', None) is None for d in myList)

Output

CodePudding user response：

You don't have to loop through the keys. Access the item you want directly and increment the counter if the item is not found, or found but None.

count = 0
for element in myList:
    if element["metaData"].get("dataOriginSystem", None) is None:
        count  = 1
print(count)

CodePudding user response：

You can try something like this...

non_existant = len([0 for item in myList if item['metaData'].get('dataOriginSystem') == None or item['metaData'].get('dataOriginSystem') == ''])
print(non_existant)

Output...