How to retrieve an element from a set without removing it?

Question

Suppose the following:

>>> s = set([1, 2, 3]) 

How do I get a value (any value) out of s without doing s.pop()? I want to leave the item in the set until I am sure I can remove it - something I can only be sure of after an asynchronous call to another host.

Quick and dirty:

>>> elem = s.pop() >>> s.add(elem) 

But do you know of a better way? Ideally in constant time.

Answer 1

Two options that don't require copying the whole set:

for e in s:     break # e is now an element from s 

Or...

e = next(iter(s)) 

But in general, sets don't support indexing or slicing.