Question

我正在尝试将数组中的值向左移动3。我要说明的是使整个代码向左旋转。

double[] x = {38, 44, 15, 11, 27, 19, 8, 12, 10};
      System.out.println("Before rotation:  ==============================");
      for (int i = 0; i < x.length; i++)
      {
         System.out.println("x[" + i + "]:  " + x[i]);
      }
      x = rotate(x, 3);
      System.out.println("After rotation:  ==============================");       
      for (int i = 0; i < x.length-3; i++)
      {

          System.out.println("x[" + i + "]:  " + x[i]);

}
}

Answer 1

最简单的方法是使用System.arraycopy：

public class Answer {
  public static void main(String[] args) {
    double[] initial = {8, 4, 5, 21, 7, 9, 18, 2, 100};
    double[] shifted = new double[initial.length];
    System.arraycopy(initial, 3, shifted, 0, initial.length - 3);

    System.out.println(Arrays.toString(shifted));
  }
}

Answer 2

下面的代码演示了如何旋转数组。

第一次arraycopy()调用将复制数组的后半部分（从rotateBy到末尾）。第二次arraycopy()调用复制了数组的开始部分（从开始到rotateBy）。

import java.util.Arrays;

public class Rotate {

  public static void main(String[] args) {
    double[] input = {8, 4, 5, 21, 7, 9, 18, 2, 100};
    double[] output = rotate(input, 3);
    System.out.println("Input:  " + Arrays.toString(input));
    System.out.println("Output: " + Arrays.toString(output));
  }

  public static double[] rotate(double[] inputArray, int rotateBy) {
    double[] output = new double[inputArray.length];
    System.arraycopy(inputArray, rotateBy, output, 0, inputArray.length - rotateBy);
    System.arraycopy(inputArray, 0, output, inputArray.length - rotateBy, rotateBy);
    return output;
  }
}

如何将数组中的值向左移动3

2 个答案: