comparing lists of tuples

Question

I have the following code, comparing two lists that contains equally structured tuples:

list_one = [('id_01','aaa','bbb'), ('id_02','aaa','bbb'), ('id_03','aaa','bbb'), ('id_04','aab','bbc')]
list_two = [('id_01','aaa','bbb'), ('id_02','aaa','bbb'), ('id_03','aad','bbd')]

for tupl in list_one:
    for tup in list_two:
        if tupl[0] == tup[0] and (tupl[1] != tup[1] or tupl[2] != tup[2]):
                print("There is a difference on "+
                      "{} between the two lists".format(tup[0]))

this code would print There is a difference on id_03 between the two lists which is the expected result. But I wonder if there is a better way to achieve the same result, maybe whitout iterating through list_two for every item of list_one, but any suggestion will be appreciated.

Answer 1

I think you would be better off using set. It provides features like set difference by itself, thereby reducing a lot of work at your end:

set_one = set([('id_01','aaa','bbb'), ('id_02','aaa','bbb'), ('id_03','aaa','bbb'), ('id_04','aab','bbc')])
set_two = set([('id_01','aaa','bbb'), ('id_02','aaa','bbb'), ('id_03','aad','bbd')])
for difference in (set_two - set_one):
    print(f"There is a difference on {difference[0]} between the two lists")

Answer 2

Looks like you should use a dictionary instead of a list. The id_01 in your case would be the key for each dictionary and the other items can be contained in a list.

Like this (same for dict_two)

dict_one = {
    'id_01': ['aaa', 'bbb'],
    'id_02': ['aaa', 'bbb'],
}

then you can iterate over the keys

for k in dict_one.keys():
    if dict_one[k][0] != dict_two[k][0] or dict_one[k][1] != dict_two[k][1]:
       print("there is a diff....")