Returns the union of two sets, optionally retaining duplicates.

返回两个集合的并集，可以选择保留重复项。

youdao

Perhaps there is some sense to this, but it strikes me as peculiar that the union of the two sets contains the float 4.0, while their intersection contains the int 4.

或许这有某种意义，但奇怪的是，这两个集的合集包含浮点数4.0，而其交集包含整数4。

youdao

For example, the UnionExpr construct (written as a | b, and representing the union of two node sets) is implemented by the class com.icl.saxon.expr.UnionExpression.

例如，UnionExpr结构(写作a | B，并表示两个节点集的联合)由com . icl . saxon . expr . unionexpression类实现。

youdao