I'm wondering if there is a quick/clean way to get the symmetric difference between two sets ?
I have:
Set<String> s1 = new HashSet<String>();
s1.add("a");
s1.add("b");
s1.add("c");
Set<String> s2 = new HashSet<String>();
s2.add("b");
I need something like:
Set<String> diff = Something.diff(s1, s2);
// diff would contain ["a", "c"]
Just to clarify I need the symmetric difference.
You can use some functions from the Google Guava library (which is really great, I strongly recommend it!):
Sets.difference(s1, s2);
Sets.symmetricDifference(s1, s2);
Javadocs for difference() and symmetricDifference()
symmetricDifference()
does exactly what you are asking for, but difference()
is also often helpful.
Both methods return a live view, but you can for example call .immutableCopy()
on the resulting set to get a non-changing set. If you don't want a view, but need a set instance you can modify, call .copyInto(s3)
. See SetView for these methods.