在检查字典列表中的值时将for循环转换为all（）

Question

I have a function that generates a list of dictionaries that looks like this:

direction_stops = [
    {
        'direction_id': 0,
        'stop_id': 1,
        'id': 'df268ccf-1291-4fce-a4c5-d348cbbb95c7',
        'sequence': 1
    },
    {
        'direction_id': 1,
        'stop_id': 1,
        'id': '55e62e15-4b44-4e71-bf5d-27c6d4fb9add',
        'sequence': 1},
    {
        'direction_id': 0,
        'stop_id': 2,
        'id': '7fde3df9-9850-49f1-86bc-511ae2913379',
        'sequence': 2
    },
    {
        'direction_id': 1,
         'stop_id': 2,
         'id': '2ed4053f-b5e0-4df1-b655-d0f23d65a698',
         'sequence': 2
     }
]

And I am trying to assert that the value for stop_id in all the dictionaries is either 1 or 2.

I have figured out how to do that using a for-loop, but I can't seem to get the following one-liner to work. Am I missing something?

all((d['stop_id'] == 1 or d['stop_id'] == 2) in d for d in direction_stops)

Answer 1

Get rid of in d .

all((d['stop_id'] == 1 or d['stop_id'] == 2) for d in direction_stops)

You can shorten the equality checks using in :

all(d['stop_id'] in {1, 2} for d in direction_stops)

Answer 2

As John Kugelman sad, you must delete in d because (d['stop_id'] == 1 or d['stop_id'] == 2) will give you boolean value. And using in d will compare it with each dictonary given by for loop. And this will give you of course false values in every comparision.