Question

I have a dictionary that looks like this:

example_dict = {
        0: [(1,2),(3,4),(3,4),(4,5)],
        1: [(1,2),(3,4),(5,6),(7,8)],
        2: [(4,5),(7,8)]}

I would like to get a sorted representation of this dictionary by number of elements in each list after ‘temporarily’ removing duplicates (only for the purpose of sorting, I don’t want to delete remove tuples). So sorted example_dict would have the following (ascending) order of keys: 2,0,1.

Is there any efficient, Pythonic way to do this?

Answer 1

print sorted(example_dict,key=lambda x: len(set(example_dict[x])))

Output:

[2, 0, 1]

Or if you want the dictionary items sorted as a list of tuples:

print sorted(example_dict.items(),key=lambda x: len(set(x[1])))

Output:

[(2, [(4, 5), (7, 8)]), (0, [(1, 2), (3, 4), (3, 4), (4, 5)]), (1, [(1, 2), (3, 4), (5, 6), (7, 8)])]