set.union() Union
Last updated: 2026-09-22
set.union() Union
set.union(*others) returns the union of set and all others.
| Category | Set Methods |
|---|---|
| Kind | Built-in Type Method |
| Python Version | all |
📝 Syntax
set.union(*others)⚙️ Parameters
| others Optional | Zero or more iterables; can be omitted. |
|---|
Returns：A new set that is the union of set and all others.
Mutates the original：No (returns a new object)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
{1, 2, 3, 4}💡 Related Cases
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❓ FAQ
QWhat is the difference between union() and the | operator?
AThe | operator requires both sides to be sets; the argument of union() can be any iterable.
QAre multiple sets supported?
AYes: {1}.union({2}, {3}) gives {1, 2, 3}.
QDoes it return a new set?
AYes, the original set is unchanged; to merge in place use update().
