Unique values in a list of lists in Python

Question

I have a list of lists as following:

G = [[1,2,3],[2,3,5],[1,2,3],[4,5,6],[4,5,6]]

How can I find count of unique lists in G?

is the list always with three integers or this is a simple idea and in theory it can be of a random number of integers? — oetoni, Nov 19 '18 at 19:26
This should help you `https://stackoverflow.com/questions/3724551/python-uniqueness-for-list-of-lists` — too_many_questions, Nov 19 '18 at 19:27
This only give unique lists. How can I find number of times that each appeared in G? — user36729, Nov 19 '18 at 19:29
Change lists to tuples and use collections.Counter ... but thats another questions. For both of wich you showed no code at all and no put no effort in it., What code _you_ came up with? — Patrick Artner, Nov 19 '18 at 19:31
`unique_data = [list(x) for x in set(tuple(x) for x in G)]; len(unique_data)` for count — d_kennetz, Nov 19 '18 at 19:31

score 3 · Accepted Answer · answered Nov 19 '18 at 19:32

If you want the count of each sublist, the easiest way is to convert them to tuples and feed them to a Counter.

from collections import Counter

G = [[1,2,3],[2,3,5],[1,2,3],[4,5,6],[4,5,6]]

print(Counter(map(tuple, G)))
# Counter({(1, 2, 3): 2, (4, 5, 6): 2, (2, 3, 5): 1})

You need the conversion to tuples because lists are not hashable, and Counter uses a dictionary internally, which requires the keys to be hashable.

Unique values in a list of lists in Python

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