Jul 18, 2022 · Converting to lists and back is a lot of unnecessary overhead and seems to defeat the purpose of sets. Consider the answer by @nyuszika7h as well as the solution in comments (ill copy here): big_set = my_sets[0].union(*my_sets[1:]) –

However, many Python programmers dislike it, including Guido himself: About 12 years ago, Python aquired lambda, reduce(), filter() and map(), courtesy of (I believe) a Lisp hacker who missed them and submitted working patches. But, despite of the PR value, I think these features should be cut from Python 3000. So now reduce().

Jul 3, 2013 · That's because the whole point of a set, both in mathematics and in almost every programming language,* is that it's not ordered: the sets {1, 2} and {2, 1} are the same set. You probably don't really want to sort those elements as strings, but as numbers (so 4.918560000 will come before 10.277200999 rather than after).

It first checks if the sets have the same length, then it checks if the sets have the same hash, and only then it performs set_issubset check. You can find the implementation of set equality check in function set_richcompare() in file setobject.c .

Jul 2, 2013 · If you want to join n sets, the best performance seems to be from set().union(*list_of_sets), which will return a new set.

set.difference, set.union... can take any iterable as the second arg while both need to be sets to use -, there is no difference in the output. Operation Equivalent Result s.difference(t) s - t new set with elements in s but not in t

Jan 7, 2013 · Yes, Python sets are mutable because we can add, delete elements into set, but sets can't contain mutable items into itself. Like the below code will give an error: s = set([[1,2,3],[4,5,6]]) So sets are mutable but can't contain mutable items, because set internally uses hashtable to store its elements so for that set elements need to be hashable.

Jun 11, 2015 · Union sets of lists/sets in Python. 1. Union of Two Set of Sets. 3. Turning list into set and union ...

Oct 16, 2015 · An alternative Python multiset implementation uses a sorted list data structure. There are a couple implementations on PyPI. One option is the sortedcontainers module which implements a SortedList data type that efficiently implements set-like methods like add , …

Jul 12, 2013 · I am having trouble with a list of sets and I think it is because I initialized it wrong, is this a valid way to initialize and add to a list of 5000 sets? sets = [set()]*5000 i = 0 for each in f:...