Question

I have a list of dictionaries that have variable depth and different keys.

for example:

a = [{attr1: 1,
     attr2: {secondary_attr1: 'sometext',
             secondary_attr2: 'sometext',
             complex_attr: {more_attr: 999}}},
     {attr1: 2}]

I am using a class to collect all the information I need from each element of the list, but of course when I try to get an item from a key that is not in that particular dictionary, I get KeyError.

Here is how I am creating the instances for each element of the list a:

InsertLine(i['attr1'],i['attr2']['secondary_attr1'])

I tried to define a simple function but it doesn’t work:

def handle_keyerror(try_key):
    try:
        try_key
        return try_key
    except KeyError: 
        return 'NULL' 

I hope I made the probem clear.

Answer 1

Your function doesn’t work because it will always return try_key. Try this.

def handle_keyerror(try_key):
    try:
        your_dictionary[try_key]
    except KeyError: 
        return None
    return try_key

Anyway it is a bad idea to check it like that.

You should rather use dict.get(key, default=None). If in dict there is no key key then it will return default value.