使用番石榴Sets.cartesianProduct的未知数量的参数
问题描述:
我被困在下面的问题:使用番石榴Sets.cartesianProduct的未知数量的参数
我有这样定义的项目的动态列表:
List<Object> itemList = ArrayList(ArrayList<Object1, Object2, Double[]>)
的Object1
和Object2
是这里不感兴趣,但数组Double[]
包含任意数量的条目。
在我的代码中,我遍历外部ArrayList
并尝试计算番石榴的cartesianProduct。到现在我有这样的事情(部分不工作的代码,对不起......):
private Set<List<Set<Double>>> getValueCombinations() {
List<Set<Double>> valuesOfInnerArrays = new ArrayList<>();
// Loop over the list of device data sets in the class and add the trim value vectors to a list for further
// processing and cartesian prooduct generation.
for (Integer indexCounter = 0; indexCounter < OuterArrayList.size(); indexCounter++) {
final List<Object> innerDataSet = (List<Object>) OuterArrayList.get(indexCounter);
final Set<Double> innerDoubleArray = ImmutableSet.of(((List<Double>) innerDataSet.get(2)).toArray(new Double[]));
valuesOfInnerArrays.add(innerDoubleArray);
}
ImmutableList<Set<Double>> test = ImmutableList.of(valuesOfInnerArrays)
// generate Cartesian product of all trim vectors = a n x m matrix of all combinations of settings
final Set<List<Set<Double>>> cartesianProduct = Sets.cartesianProduct(ImmutableList.of(valuesOfInnerArrays));
return cartesianProduct;
}
在我发现所有的例子,他们总是叫笛卡儿积与已知的设置,这是我不能做:
Set<Double> first = ImmutableSet.of(1., 2.);
Set<Double> second = ImmutableSet.of(3., 4.);
Set<List<Double>> result =
Sets.cartesianProduct(ImmutableList.of(first, second));
我最后想要的是存储在内部Double []数组中的所有数字的联合。
任何帮助表示赞赏。
答
感谢the Post "Java Guava CartesianProduct"我解决了我的问题。我的最终解决方案是这样的:
private Set<List<Double>> getValueCombinations() {
final List<Set<Double>> valuesOfInnerArrays = new ArrayList<>();
// Loop over the list of device data sets in the class and add the value vectors to a list for further
// processing and cartesian product generation.
for (Integer indexCounter = 0; indexCounter < outerArrayList.size(); indexCounter++) {
final List<Object> innerDataSet = (List<Object>) deviceDataSets.get(indexCounter);
final SortedSet<Double> >innerDoubleArray = new TreeSet<>((List<Double>) innerDataSet.get(2));
valuesOfInnerArrays.add(innerDoubleArray);
}
return Sets.cartesianProduct(valuesOfInnerArrays);
}
此外,我改变了我的输入列表的格式:
List<Object> itemList = ArrayList(ArrayList<Object1, Object2, List<Double>>)