如何在c#中连接两个数组?

int[] x = new int [] { 1, 2, 3};
int[] y = new int [] { 4, 5 };

int[] z = // your answer here...

Debug.Assert(z.SequenceEqual(new int[] { 1, 2, 3, 4, 5 }));

- - -

Right now I use

现在我使用

int[] z = x.Concat(y).ToArray();

Is there an easier or more efficient method?

有没有更简单或更有效的方法?

21 个解决方案

#1

259

var z = new int[x.Length + y.Length];
x.CopyTo(z, 0);
y.CopyTo(z, x.Length);

#2

Try this:

试试这个:

List<int> list = new List<int>();
list.AddRange(x);
list.AddRange(y);
int[] z = list.ToArray();

#3

You could write an extension method:

您可以编写一个扩展方法:

public static T[] Concat<T>(this T[] x, T[] y)
{
    if (x == null) throw new ArgumentNullException("x");
    if (y == null) throw new ArgumentNullException("y");
    int oldLen = x.Length;
    Array.Resize<T>(ref x, x.Length + y.Length);
    Array.Copy(y, 0, x, oldLen, y.Length);
    return x;
}

Then:

然后:

int[] x = {1,2,3}, y = {4,5};
int[] z = x.Concat(y); // {1,2,3,4,5}

#4

I settled on a more general-purpose solution that allows concatenating an arbitrary set of one-dimensional arrays of the same type. (I was concatenating 3+ at a time.)

我选择了一种更通用的解决方案，它允许将同一类型的任意一组一维数组连接在一起。(我一次连接了3+。)

My function:

我的函数:

    public static T[] ConcatArrays<T>(params T[][] list)
    {
        var result = new T[list.Sum(a => a.Length)];
        int offset = 0;
        for (int x = 0; x < list.Length; x++)
        {
            list[x].CopyTo(result, offset);
            offset += list[x].Length;
        }
        return result;
    }

And usage:

和用法:

        int[] a = new int[] { 1, 2, 3 };
        int[] b = new int[] { 4, 5, 6 };
        int[] c = new int[] { 7, 8 };
        var y = ConcatArrays(a, b, c); //Results in int[] {1,2,3,4,5,6,7,8}

#5

This is it:

就是这样:

using System.Linq;

int[] array1 = { 1, 3, 5 };
int[] array2 = { 0, 2, 4 };

// Concatenate array1 and array2.
var result1 = array1.Concat(array2);

#6

You can take the ToArray() call off the end. Is there a reason you need it to be an array after the call to Concat?

您可以使用ToArray()调用结束。有什么原因你需要它作为一个数组在调用Concat之后?

Calling Concat creates an iterator over both arrays. It does not create a new array so you have not used more memory for a new array. When you call ToArray you actually do create a new array and take up the memory for the new array.

调用Concat在两个数组上创建一个迭代器。它不会创建新的数组，因此您不会为新数组使用更多的内存。当您调用ToArray时，实际上确实创建了一个新的数组，并为新数组占用内存。

So if you just need to easily iterate over both then just call Concat.

因此，如果你只需要简单地迭代，然后调用Concat。

#7

I know the OP was only mildly curious about performance. That larger arrays may get a different result (see @kurdishTree). And that it usually does not matter (@jordan.peoples). None the less, I was curious and therefore lost my mind ( as @TigerShark was explaining).... I mean that I wrote a simple test based on the original question.... and all the answers....

我知道OP只是对性能有点好奇。更大的数组可能会得到不同的结果(见@kurdishTree)。而这通常并不重要(@jordan.people)。然而，我很好奇，因此失去了理智(正如@TigerShark所解释的)我的意思是,我写了一个简单的测试基于原始问题....和所有的答案....