Get list and merge it with another located in a dataframe

Question

I have a list of dictionaries like the following

dict = [{'id': 123, 'slot': 4}, {'id': 435, 'slot': 4}, {'id': 435, 'slot': 5}]

and a dataframe like

list_of_old_ids slot
[121,432]       4
[222,674]       5

and I would like to get the ids of the dict in a list and then merge that list with the one of the dataframe to get the following

list_of_new_ids   slot
[121,432,123,435] 4
[222,674,435]     5

How can I do it? I've tried with str(list(map(itemgetter('id'), dict))) but then I cannot merge it with the dataframe column. Many thanks.

Answer 1

Try this, which should be pretty fast:

new_df = pd.concat([df.explode('list_of_old_ids').rename({'list_of_old_ids':'id'},axis=1), pd.DataFrame(dict)]).groupby('slot').agg(list).reset_index()

Output:

>>> new_df
   slot                    id
0     4  [121, 432, 123, 435]
1     5       [222, 674, 435]