在数组C#中移动元素 [英] Moving elements in array c#

问题描述

我有一个非常简单的数组，希望可以在其中移动某些项.在c#中是否有内置工具可以做到这一点?如果没有，那么您对此有任何建议.

I have this very simple array which I want to be able to move around some items in. Are there any built in tools in c# to do this? If not, du you have any suggestion in how to do it.

例如

var smallArray = new string[4];
smallArray[0] = "a";
smallArray[1] = "b";
smallArray[2] = "c";
smallArray[3] = "d";

并且可以说我想(以编程方式)移动索引2和0，创建

And lets say I want to (programmatically) shift index 2 and 0, creating

smallArray[0] = "c";
smallArray[1] = "a";
smallArray[2] = "b";
smallArray[3] = "d";

谢谢.

推荐答案

好的，现在您已经更改了示例，没有内置的内容-写起来实际上有点麻烦...例如，您需要考虑将其向上"移动和向下"移动的情况.您需要单元测试，但是我认为这应该做到...

Okay, now you've changed the example, there's nothing built-in - and it would actually be a bit of a pain to write... you'd need to consider cases where you're moving it "up" and where you're moving it "down", for example. You'd want unit tests, but I think this should do it...

public void ShiftElement<T>(this T[] array, int oldIndex, int newIndex)
{
    // TODO: Argument validation
    if (oldIndex == newIndex)
    {
        return; // No-op
    }
    T tmp = array[oldIndex];
    if (newIndex < oldIndex) 
    {
        // Need to move part of the array "up" to make room
        Array.Copy(array, newIndex, array, newIndex + 1, oldIndex - newIndex);
    }
    else
    {
        // Need to move part of the array "down" to fill the gap
        Array.Copy(array, oldIndex + 1, array, oldIndex, newIndex - oldIndex);
    }
    array[newIndex] = tmp;
}

您可能应该考虑使用List<T>而不是数组，该数组允许您在特定索引处插入和删除.这两个操作比仅复制相关部分要昂贵得多，但可读性更高.

You should probably consider using a List<T> instead of an array, which allows you to insert and remove at particular indexes. Those two operations will be more expensive than only copying the relevant section, but it'll be a lot more readable.

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