How to join two sets in one line without using "|"

Assume that S and T are assigned sets. Without using the join operator |, how can I find the union of the two sets? This, for example, finds the intersection:

S = {1, 2, 3, 4}
T = {3, 4, 5, 6}
S_intersect_T = { i for i in S if i in T }

So how can I find the union of two sets in one line without using |?

Solution 1:

You can use union method for sets: set.union(other_set)

Note that it returns a new set i.e it doesn't modify itself.

Solution 2:

You could use or_ alias:

>>> from operator import or_
>>> from functools import reduce # python3 required
>>> reduce(or_, [{1, 2, 3, 4}, {3, 4, 5, 6}])
set([1, 2, 3, 4, 5, 6])

Solution 3:

If you are fine with modifying the original set (which you may want to do in some cases), you can use set.update():

S.update(T)

The return value is None, but S will be updated to be the union of the original S and T.