Redis: how to efficiently check for empty nested key

Question

I have a nested dictionary in my redis store and need to find all records where key_2 == "" then return value in key_3. All key_3 values will then be used to run mysql query to get key_2 value and update the redis store.

[
  ...
  task_44903: {"key_1": 44903, "key_2": "", "key_3": 1}
  task_44229: {"key_1": 44229, "key_2": 4, "key_3": 2}
  ...
]

My current way of achieving this is

    keys = r.keys(pattern='task_*')
    key_3 = set()
    for key in keys:
        values = r.get(key).decode('utf-8')
        values = ast.literal_eval(values)
        if values['key_2'] == '':
            key_3.add(values['key_3'])   

Is there a more concise way of achieving this?

Answer 1

I'm not sure if this is what you wanted.

data = [
  {'task_44903': {"key_1": 44903, "key_2": "", "key_3": 1}},
  {'task_44229': {"key_1": 44229, "key_2": "", "key_3": 1}},
  {'task_44230': {"key_1": 44229, "key_2": "", "key_3": 2}}
]

set([ v['key_3'] for item in data for _, v in item.items()  if v['key_2']==""])

Output

{1, 2}