用数字范围填充数组 [英] Fill arrays with ranges of numbers

问题描述

是否有任何语法/包允许使用数字范围快速填充 java 数组，例如在 perl 中?

Is there any syntax/package allowing quick filling of java arrays with ranges of numbers, like in perl?

例如

int[] arr = new int[1000];
arr=(1..500,301..400,1001..1400); // returns [1,2,3,4,...,500,301,302,...,400,1001,1002,...1400]

此外，这里有一个包，它允许获取上述数字列表中的第 n 个数字，而无需实际创建数组(可能很大)?

Also, it here a package that allows getting the n-th number in such list of numbers as the above, without actually creating the array (which can be huge)?

例如

BunchOfRangesType bort = new BunchOfRangesType("1..500","301..400","1001..1400");
bort.get(0); // return 1
bort.get(500); // return 301
bort.get(501); // return 302

实施起来并不难，但我想这可能很常见，所以可能已经完成了.

It's not too difficult to implement, but I guess it might be common so maybe it was already done.

推荐答案

不像 True Soft 的回答那么干净，但你可以使用 Google Guava 达到同样的效果:

Not quite as clean as True Soft's answer, but you can use Google Guava to the same effect:

public class Test {

    public static void main(String[] args) {
        //one liner
        int[] array = toArray(newLinkedList(concat(range(1, 10), range(500, 1000))));

        //more readable
        Iterable<Integer> values = concat(range(1, 10), range(500, 1000));
        List<Integer> list = newLinkedList(values);
        int[] array = toArray(list);

    }

    public static List<Integer> range(int min, int max) {
        List<Integer> list = newLinkedList();
        for (int i = min; i <= max; i++) {
            list.add(i);
        }

        return list;
    }

}

请注意，您需要一些静态导入才能使其工作.

Note you need a few static imports for this to work.

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