Example of double list comprehension in python3

double_list_comprehension.py

# Example of double list comprehension in python
# example key = some_numbers-some_more_numbers-message_id

found_keys = [key for message_id in all_messageids for key in returned_keys if key.endswith(message_id)]
print(found_keys)

# Following results in same but in the long way
found_keys = []
for key in returned_keys: 
    for message_id in all_messageids:
        if key.endswith(message_id):
            found_keys.append(key)
print(found_keys)