DataFrame.fullJoin()计算具有不同名称的列的笛卡尔积。

val numberColumn:DataColumn<Int> = columnOf(1, 2).rename("numbers")
val charColumn:DataColumn<String> = columnOf("a", "b").rename("chars")

val carthesianProduct:DataFrame<Any?> = numbers.toDataFrame().fullJoin(charColumn.toDataFrame())

carthesianProduct.toString()

numbers chars
 0       1     a
 1       1     b
 2       2     a
 3       2     b