2D数组的CopyOfRange

Question

Is there any similar command to Arrays.copyOfRange(short[] original, int from, int to) for 2D arrays in Java?

If there is not, is there any straightforward way to copy columns or rows of 2D array without using for loops?

Answer 1

copy columns

1) you can copy columns just using Arrays.copyOfRange

    String[][] sss = { {"1", "2"}, {"3", "4"}};
    String[][] sss1 = Arrays.copyOfRange(sss, 0, 1); // ss = {{"1", "2"}}

2) for copy rows without loop you can use Stream Api

 Arrays.stream(sss).map(s1 -> Arrays.stream(s1).skip(1).limit(1).toArray()).toArray(); // return {{"2"},{"4"}}

3) "This does a shallow copy;"

Ok, use Stream Api we can do not shallow copy:

Arrays.stream(sss).skip(1).limit(1).map(s1 -> Arrays.stream(s1).toArray()).toArray(); // return {{"3", "4"}}