.NET矩形数组: how to access in a loop?

Question

基本上你有两种方法可以做到这一点:

for (int x = 0; x < UPPER_X; x++)
    for (int y = 0; y < UPPER_Y; y++)
    {        
        arr1[x, y] = get_value();
        arr2[y, x] = get_value();
    }

唯一的区别是在内循环中更改哪个变量:第一个或第二个。我听说不同语言的结果有所不同。

.NET 的正确顺序是什么？

Answer 1

您应该对您的特定情况进行基准测试以确定。

您可能会认为矩形数组(即连续分配的内存)没有区别，但根据此 MSDN article有一个区别:

You can get even better results by converting a multidimensional array into a single-dimensional array. If you don't mind the syntax, this can be trivial; just use one index as an offset. For example, the following declares a single-dimensional array to be used as a two-dimensional array:

double[] myArray = new double[ROW_DIM * COLUMN_DIM];

For indexing the elements of this array, use the following offset:

myArray[row * COLUMN_DIM + column];

This will undoubtedly be faster than an equivalent jagged or rectangular array.