Taking the union of sets

Question

I have a list l of sets. To take the union of all the sets in l I do:

union = set()
for x in l:
   union |= x

I have a feeling there is a more economical/functional way of writing this. Can I improve upon this?

Answer 1

Here's how I would do it (some corrections as per comments):

union_set = set()
union_set.update(*l)

or

union_set = set.union(*l)

Answer 2

>>> l = [set([1, 2, 3]), set([3, 4, 5]), set([0, 1])]
>>> set.union(*l)
set([0, 1, 2, 3, 4, 5])