C# 将数组的元素移动到特定点，并将特定元素拉到前面

Question

我的问题是我想在数组中有一个特定的元素，将它复制到另一个变量，将整个数组右移到那个元素，然后把这个元素放在前面。在漂亮的绘图中，它看起来像这样。

[0, 1, 2, 3, 4, 5]
          ^

[0, 1, 2, null, 4, 5]
          ^ (3)

[null, 0, 1, 2, 4, 5]
             ^ (3)

[null, 0, 1, 2, 4, 5]
 ^ (3)

[3, 0, 1, 2, 4, 5]
 ^

我已经尝试使用 for 循环将元素放在前面，然后插入 3，但我担心我的方法不是最有效或最快的方法。

这是我尝试过的。

        int elementAt = 3;
        int[] array = { 0, 1, 2, 3, 4, 5 };
        int mem = array[elementAt];
        for (int i = elementAt; i > 0; i--)
            array[i] = array[i - 1];
        array[0] = mem;

我怀疑像 Array.Copy 这样的东西可以做得更快......？

编辑:下面的每个答案在特定情况下都有自己的用途。这个问题没有确定的答案，让这些结果让你选择使用哪种方法。

iterations, index, arraysize
HIGH, HIGH, HIGH
Speed for ShiftRightAt: 6616, ticks: 28007912
Speed for shiftlist: 3556, ticks: 15054635
Speed for arrayCopy: 1742, ticks: 7376152
Speed for MoveValueToFront: 67, ticks: 285901
LOW, LOW, HIGH
Speed for ShiftRightAt: 0, ticks: 28
Speed for shiftlist: 42, ticks: 180476
Speed for arrayCopy: 33, ticks: 142717
Speed for MoveValueToFront: 0, ticks: 67
HIGH, LOW, HIGH
Speed for ShiftRightAt: 0, ticks: 1399
Speed for shiftlist: 3624, ticks: 15341777
Speed for arrayCopy: 3177, ticks: 13449012
Speed for MoveValueToFront: 0, ticks: 926
LOW, HIGH, HIGH
Speed for ShiftRightAt: 73, ticks: 311428
Speed for shiftlist: 41, ticks: 174652
Speed for arrayCopy: 18, ticks: 79768
Speed for MoveValueToFront: 65, ticks: 277266
HIGH, HIGH, LOW
Speed for ShiftRightAt: 0, ticks: 1379
Speed for shiftlist: 0, ticks: 3902
Speed for arrayCopy: 0, ticks: 728
Speed for MoveValueToFront: 0, ticks: 914
LOW, LOW, LOW
Speed for ShiftRightAt: 0, ticks: 3
Speed for shiftlist: 0, ticks: 32
Speed for arrayCopy: 0, ticks: 11
Speed for MoveValueToFront: 0, ticks: 12
HIGH, LOW, LOW
Speed for ShiftRightAt: 0, ticks: 135
Speed for shiftlist: 0, ticks: 3850
Speed for arrayCopy: 0, ticks: 998
Speed for MoveValueToFront: 0, ticks: 840
LOW, HIGH, LOW
Speed for ShiftRightAt: 0, ticks: 15
Speed for shiftlist: 0, ticks: 16
Speed for arrayCopy: 0, ticks: 9
Speed for MoveValueToFront: 0, ticks: 39

测试方法: https://pastebin.com/HKkixHGR

Answer 1

你的漂亮图画正好给出了你需要写的东西。

public static void ShiftRightAt<T>(T[] array, int index)
{
    if (index < 0 || index >= array.Length) return; // throw exception

    var element = array[index]; // take out the element

    for (int i = index; i > 0; i--)
    {
        array[i] = array[i - 1];
    }

    array[0] = element;
}